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The Eclipse Jetty Operations Guide targets sysops, devops, and developers who want to install Eclipse Jetty as a standalone server to deploy web applications.

If you are new to Eclipse Jetty, read on to download, install, start and deploy web applications to Jetty.

Jetty is distributed in an artifact that expands in a directory called

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, which should not be modified.

Configuration for Jetty is typically done in a directory called

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34. There may be more than one

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directories with different configurations.

Jetty supports the deployment of EE8, EE9 and EE10 standard web applications, as well as the deployment of Jetty-specific web applications.

For example, the following commands can be used to set up a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory that supports deployment of EE10

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 files and a clear-text HTTP connector:

$ export JETTY_HOME=/path/to/jetty-home $ mkdir /path/to/jetty-base $ cd /path/to/jetty-base $ java -jar $JETTY_HOME/start.jar --add-modules=server,http,ee10-deploy

The last command creates a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

38 directory and other directories that contain the configuration of the server, including the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

39 directory, in which standard EE10

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 files can be deployed.

To deploy Jetty’s demo web applications, run this command:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Now you can start the Jetty server with:

$ java -jar $JETTY_HOME/start.jar

Point your browser at

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

41 to see the demo web applications deployed in Jetty.

The Jetty server can be stopped with

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

42 in the terminal window.

Read the for more information about Jetty modules,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 and how to customize and start Jetty.

The Jetty distribution is available in both

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

45 and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

46 formats; download the one most appropriate for your system, typically

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

45 for Windows and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

46 for other operating systems.

After the download, unpacking Jetty will extract the files into a directory called

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

49, where

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

50 is the version of Jetty that you downloaded. For example, installing Jetty 12.0.6 will create a directory called

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

51.

It is important that only stable release versions are used in production environments. Versions that have been deprecated or are released as Milestones [M], Alpha, Beta or Release Candidates [RC] are not suitable for production as they may contain security flaws or incomplete/non-functioning feature sets.

Unpack Jetty file into a convenient location, such as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

52. The rest of the instructions in this documentation will refer to this location as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, or

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

54.

For Windows users, you should unpack Jetty to a path that does not contain spaces.

Jetty as a standalone server has no graphical user interface; configuring and running the server is done from the command line.

First, create a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

You will typically start Jetty by executing

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

56 from this directory. However, if you try to start Jetty from an empty

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, it will complain that you haven’t enabled any modules:

$ java -jar $JETTY_HOME/start.jar

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

Jetty uses a to configure and assemble the server; these modules are enabled and configured in . Since the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory you just created is empty, Jetty has no configuration it can use to assemble the server.

See the of this document for more information on the design of Jetty’s module system.

You can explore what modules are available with the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

60 flag:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

Now try to enable the module.

If you want to enable support for protocols like secure HTTP/1.1 or HTTP/2 or HTTP/3, or want to configure Jetty behind a load balancer, read .

$ java -jar $JETTY_HOME/start.jar --add-modules=http

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

When Jetty enables the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module, it also automatically enables a number of transitive dependencies of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module, such as the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

65 module, and so on.

You can now start Jetty:

$ java -jar $JETTY_HOME/start.jar

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Jetty is listening on port

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

66 for clear-text HTTP/1.1 connections. But since it has no web applications deployed, it will just reply with

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

67 to every request.

Before you , take a moment to see what happened to the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory once you enabled the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

70 file configures the server’s logging level; this file was auto-generated when the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

71 module was activated as a transitive dependency of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module. 2 The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

73 directory contains the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 configuration files for any modules you have explicitly activated. 3 The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

75 file is the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module configuration file, where you can specify values for the .

By default, Jetty does not generate

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 configuration files in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

73 for modules activated as transitive dependencies. To manually configure such modules, you should activate them directly via Jetty’s

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

80 flag.

In the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

81 file you can find the following [among other contents]:

http.ini

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 This line enables the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module and should not be modified. 2 This commented line specifies the default value for the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

83 property, which is the network port that Jetty uses to listen for clear-text HTTP connections.

Try changing the default port. Open

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

81, uncomment the line containing

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

85, and change its value to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

86:

http.ini

$ java -jar $JETTY_HOME/start.jar --add-module=demos

If you restart Jetty, it will use this new value:

$ java -jar $JETTY_HOME/start.jar

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You can also specify the value of a module property when you start up Jetty. A property value specified on the command-line in this way will override the value configured in a module’s

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 file.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

For more detailed information about the Jetty start mechanism, you can read the section.

You can deploy two types of web application resources with Jetty:

Standard Web Application Archives, in the form of $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 37 files or web application directories, defined by the Servlet specification. Their deployment is described in .
Jetty context XML files, that allow you to customize the deployment of standard web applications, and also allow you to use Jetty components — and possibly custom components written by you — to assemble and deploy your web applications. Their deployment is described in .

Jetty supports the deployment of both standard web applications and Jetty context XML files in a specific EE environment, such as the old Java EE 8, or Jakarta EE 9, or Jakarta EE 10.

Jetty supports simultaneous deployment of web applications each to a possibly different environment, for example an old Java EE 8 web application alongside a new Jakarta EE 10 web application.

Refer to the section about for further information about how to deploy to different environments.

In the following sections you can find simple examples of deployments of Jakarta EE 10 web applications.

A standard Servlet web application is packaged in either a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file or in a directory with the structure of a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file.

Recall that the structure of a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file is as follows:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 Publicly accessible resources such as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

92,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

93,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

94,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

95 files, etc. are placed in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 or in sub-directories of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37. 2

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

98 is a special directory used to store anything related to the web application that must not be publicly accessible, but may be accessed by other resources. 3

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

99 stores the web application’s compiled

$ java -jar $JETTY_HOME/start.jar

00 files 4

$ java -jar $JETTY_HOME/start.jar

01 stores the web application’s

$ java -jar $JETTY_HOME/start.jar

02 files 5

$ java -jar $JETTY_HOME/start.jar

03 is the web application deployment descriptor, which defines the components and the configuration of your web application.

To deploy a standard web application, you need to enable the .

The following examples assume you’re deploying a Jakarta EE 10 application; for other versions of Jakarta EE, make sure to activate the corresponding

$ java -jar $JETTY_HOME/start.jar

05 module.

Refer to the section about for further information about how to deploy to different environments.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

$ java -jar $JETTY_HOME/start.jar

The

$ java -jar $JETTY_HOME/start.jar

04 module creates

$ java -jar $JETTY_HOME/start.jar

07, which is the directory where Jetty looks for any

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 files or web application directories to deploy.

Activating one of Jetty’s

$ java -jar $JETTY_HOME/start.jar

05 modules enables web application deployment. Whether these web applications are served via clear-text HTTP/1.1, or secure HTTP/1.1, or secure HTTP/2, or HTTP/3 [or even all of these protocols] depends on whether the correspondent Jetty protocol modules have been enabled. Refer to the for further information.

Now you’re ready to copy a web application to the

$ java -jar $JETTY_HOME/start.jar

07 directory. You can use one of the demos shipped with Jetty:

$ java -jar $JETTY_HOME/start.jar

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory is now:

$ java -jar $JETTY_HOME/start.jar

Now start Jetty:

$ java -jar $JETTY_HOME/start.jar

Note the highlighted line that logs the deployment of

$ java -jar $JETTY_HOME/start.jar

12.

Now you can access the web application by pointing your browser to

$ java -jar $JETTY_HOME/start.jar

13.

If you want to customize the deployment of your web application — for example, by specifying a

$ java -jar $JETTY_HOME/start.jar

14 different from the file/directory name, or by specifying JNDI entries, or by specifying virtual hosts — read .

Jetty is an HTTP server and Servlet Container, and supports deployments of web applications.

Clients send HTTP requests for specific URIs, such as

$ java -jar $JETTY_HOME/start.jar

15.

The HTTP requests arrive to the connectors through the network; the Jetty server processes the requests and, based on their URIs, forwards them to the appropriate .

There are three main concepts on which the Jetty standalone server is based:

The , where Jetty modules provides Jetty features.
The , that provides a place where you configure which Jetty modules you want to enable, configure the properties of each enabled module, and therefore configure the features you need for your web applications.
The , that starts a JVM that runs Jetty with the configuration you specified.

The Jetty standalone server is made of Java components that are assembled together, configured and started to provide different features.

A Jetty module provides one or more components that work together to provide typically one feature, although they may provide more than one feature.

A Jetty module is nothing more than Jetty components assembled together like you would do using Java APIs, just done in a declarative way using configuration files. What you can do in Java code to assemble Jetty components can be done using Jetty modules.

A Jetty module may be dependent on other Jetty modules: for example, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 Jetty module depends on the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 Jetty module which in turn depends on the

$ java -jar $JETTY_HOME/start.jar

19 and

$ java -jar $JETTY_HOME/start.jar

20 Jetty modules.

Every feature in a Jetty server is enabled by enabling the corresponding Jetty module[s].

For example, if you enable only the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 Jetty module, then your Jetty standalone server will only be able to listen to a network port for clear-text HTTP requests. It will not be able to process secure HTTP [i.e.

$ java -jar $JETTY_HOME/start.jar

requests, it will not be able to process WebSocket, or HTTP/2, or HTTP/3 or any other protocol because the correspondent modules have not been enabled.

You can even start a Jetty server without listening on a network port — for example because you have enabled a custom module you wrote that provides the features you need.

This allows the Jetty standalone server to be as small as necessary: modules that are not enabled are not loaded, don’t waste memory, and you don’t risk a client using a module that you did not know was even there.

For more detailed information about the Jetty module system, see .

Instead of managing multiple Jetty distributions out of many locations, it is possible to maintain a separation between the binary installation of the standalone Jetty, known as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, and the customizations for your specific environment[s], known as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34.

This separation between the binary installation directory and the specific configuration directory allows managing multiple, different, server configurations, and allows for quick, drop-in upgrades of Jetty.

There should always only be one

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 [per version of Jetty], but there can be many

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directories that reference it.

This separation between

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 allows Jetty upgrades without affecting your web applications.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 contains the Jetty runtime and libraries and the default configuration, while a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 contains your web applications and any override of the default configuration.

For example, with the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 installation the default value for the network port for clear-text HTTP is

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

66. However, you may want that port to be

$ java -jar $JETTY_HOME/start.jar

35, because that is configured to forward to the backend on port

$ java -jar $JETTY_HOME/start.jar

35. In this case, you configure the clear-text HTTP port in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, not in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33. When you upgrade Jetty, you will upgrade only the files in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, and all the configuration in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 will remain unchanged, keeping your clear-text HTTP port at

$ java -jar $JETTY_HOME/start.jar

35.

Installing the Jetty runtime and libraries in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 also allows you to leverage file system permissions:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 may be owned by an administrator user [so that only administrators can upgrade it], while

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directories may be owned by a less privileged user.

If you had changed the default configuration in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, when you upgrade Jetty, say from version

$ java -jar $JETTY_HOME/start.jar

46 to version

$ java -jar $JETTY_HOME/start.jar

47, your changes would be lost. Maintaining all the changes in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, and having to reconfigure these with each upgrade results in a massive commitment of time and effort.

To recap:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

This is the location for the Jetty binaries.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

This is the location for your configurations and customizations to the Jetty binaries.

The Jetty start mechanism provides two features:

The mean to configure your $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 34 by enabling the desired modules, and to display the configuration of your $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 34.
The mean to start Jetty itself, by starting a JVM that reads the Jetty configuration in $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 34, which is then executed to assemble and start the Jetty components.

The Jetty start mechanism is invoked by executing

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

56 from within your

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, and you can think of it as the Jetty command line program, similar to many Unix/Windows command line programs.

For example, you can ask for help:

$ java -jar $JETTY_HOME/start.jar

Or you can list all available modules [or only those with a specific tag]:

$ java -jar $JETTY_HOME/start.jar

You can enable a module, for example the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

Once you have one or more module enabled, you can display the current configuration, to verify that the configuration is correct:

$ java -jar $JETTY_HOME/start.jar

You can enable a Jetty demo module, which will deploy a demo web application:

$ java -jar $JETTY_HOME/start.jar

Finally, you can start Jetty:

$ java -jar $JETTY_HOME/start.jar

The Jetty start mechanism is invoked by executing

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

56, from within a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory, with zero or more command line options:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The Jetty start mechanism has two main modes of operation:

The tool mode, detailed in , when it is used as a command line tool to configure the $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 34 directory by enabling modules, creating sub-directories and files, downloading files, etc. In this mode, the JVM started with $ java -jar $JETTY_HOME/start.jar 60 performs the specified command and then exits.
The start mode, detailed in , when it is used to start the JVM that runs Jetty with the specified configuration. In this mode, the JVM started with $ java -jar $JETTY_HOME/start.jar 60 starts Jetty and does not exit until stopped, for example by hitting Ctrl+C on the terminal.

Within the Jetty start mechanism, the source of configurations is layered in this order, from higher priority to lower priority:

The command line options.
The $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 34 directory, and its files.
The directory specified with the $ java -jar $JETTY_HOME/start.jar 63 option, and its files.
The $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 33 directory, and its files.

You can enable Jetty modules persistently across restarts with the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

80 command:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The Jetty start mechanism will look for the specified modules following the order specified above. In the common case [without a

$ java -jar $JETTY_HOME/start.jar

63 directory], it will look in

$ java -jar $JETTY_HOME/start.jar

67 first and then in

$ java -jar $JETTY_HOME/start.jar

68.

Since the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 modules are standard Jetty modules, they are present in

$ java -jar $JETTY_HOME/start.jar

68 and loaded from there.

When you enable a Jetty module, the Jetty start mechanism:

Creates the correspondent $ java -jar $JETTY_HOME/start.jar 72 module configuration file. The content of these $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 74 files is copied from the $ java -jar $JETTY_HOME/start.jar 74 section of the correspondent $ java -jar $JETTY_HOME/start.jar 75 file.
Executes the directives specified in $ java -jar $JETTY_HOME/start.jar 76 section [if present] of the $ java -jar $JETTY_HOME/start.jar 75 file. This may simply create a file or a directory, or download files from the Internet. This step is performed transitively for all module dependencies.

For example, enabling the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 modules results in the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory to have the following structure:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

$ java -jar $JETTY_HOME/start.jar

81 is created by the

$ java -jar $JETTY_HOME/start.jar

76 directives of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

65 module, which is a transitive dependency of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module.

A module is enabled because the correspondent

$ java -jar $JETTY_HOME/start.jar

72 file contains a

$ java -jar $JETTY_HOME/start.jar

86 directive.

Commenting out the

$ java -jar $JETTY_HOME/start.jar

86 directive effectively disables the module.

Deleting the correspondent

$ java -jar $JETTY_HOME/start.jar

72 file also disables the module.

You can now edit the

$ java -jar $JETTY_HOME/start.jar

72 configuration files, typically by uncommenting properties to change their default value.

The

$ java -jar $JETTY_HOME/start.jar

72 configuration file may be missing, if the correspondent module is a transitive dependency. You can easily generate the configuration file by explicitly enabling the module, for example to generate the

$ java -jar $JETTY_HOME/start.jar

92 configuration file you would issue the following command [the module order does not matter]:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory structure is now:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

You want to edit the

$ java -jar $JETTY_HOME/start.jar

72 configuration files so that the configuration is applied every time Jetty is started [or re-started].

For example,

$ java -jar $JETTY_HOME/start.jar

95 contains the following property, commented out:

You can change the clear-text HTTP port Jetty listens to by uncommenting that property and changing its value:

When Jetty is started [or re-started] this configuration is applied and Jetty will listen for clear-text HTTP/1.1 on port

$ java -jar $JETTY_HOME/start.jar

96.

You can also enable a module transiently, only for the current execution of the

$ java -jar $JETTY_HOME/start.jar

60 command.

If you have an empty

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, the following command enables the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 modules, but does not create any

$ java -jar $JETTY_HOME/start.jar

72 files.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Since there are no

$ java -jar $JETTY_HOME/start.jar

72 files, you can only customize the properties via the command line, for example:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Enabling modules on the command line is useful to verify that the modules work as expected, or to try different configurations.

It is possible to enable some module persistently via

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

80 and some other module transiently via

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

04.

Remember that once the current execution terminates, the modules enabled transiently on the command line via

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

04 and their configuration are not saved and will not be enabled on the next execution [unless you specify them again on the command line].

You can add your own modules by adding a

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

06 file.

For example, you may want to add a Postgres JDBC driver to the server class-path, to avoid that each deployed web application bring its own version. This allows you to control the exact Postgres JDBC driver version for all web applications.

Create the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

07 file:

postgresql.mod

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Then enable it:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Enabling the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

08 module will execute the

$ java -jar $JETTY_HOME/start.jar

76 directive [downloading the

$ java -jar $JETTY_HOME/start.jar

02 file from Maven Central if not already present] and create the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

11 with the content of the

$ java -jar $JETTY_HOME/start.jar

74 section.

The

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

13 section ensures that the specified file is in the server class-path when Jetty is started.

Using a custom Jetty module, you can customize the JVM startup options.

This is useful if you need to start Jetty and want to specify JVM options such as:

java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 14, to specify the max heap size
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 15, to specify the GC log file and options
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 16, to specify Java agents
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 17 options, for example to specify the GC implementation
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 18, to enable Java preview features

Start by creating

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

19:

jvm.mod

$ java -jar $JETTY_HOME/start.jar

Enable it:

$ java -jar $JETTY_HOME/start.jar

Since the module defines an

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

20 section, it will fork another JVM when Jetty is started.

This means that when you start Jetty, there will be two JVMs running: one created by you when you run

$ java -jar $JETTY_HOME/start.jar

60, and another forked by the Jetty start mechanism with the JVM options you specified [that cannot be applied to an already running JVM].

The second JVM forked by the Jetty start mechanism when one of the modules requires forking, for example a module that contains an

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

20 section, may not be desirable, and may be avoided as explained in .

Once you have enabled and configured the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, you can display the configuration to verify that it is correct.

Using the standard

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 and

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 Jetty modules, and the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

08 and

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

27 custom Jetty module defined above, you obtain:

$ java -jar $JETTY_HOME/start.jar

Note how the configuration displayed above includes:

In the list of enabled modules, the java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
08 and
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 27 modules
In the list of JVM arguments, those specified by the java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 27 module
In the server class-path, the
$ java -jar $JETTY_HOME/start.jar 02 file specified by the
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 08 module

The Jetty start mechanism can display a full JVM command line that will start Jetty with the configuration you specified, with the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 option:

$ java -jar $JETTY_HOME/start.jar

The full JVM command line generated by

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 can be split in various parts that can be used individually, for example in scripts.

Furthermore, Jetty modules may specify the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

35 option that will fork a second JVM to start Jetty, which may not be desirable. Some option, such as

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36, imply

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

35, as it won’t be possible to modify the module-path in the already started JVM.

To start Jetty without forking a second JVM, the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 option can be used to generate a command line that is then executed so that starting Jetty only spawns one JVM.

You can use the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 option as explained below to avoid forking a second JVM when using modules that have the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

20 section, or the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

35 option, or when using the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option.

For example, using the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 option with the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

44 introduced in produces the following command line:

$ java -jar $JETTY_HOME/start.jar

You can then run the generated command line.

For example, in the Linux

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

45 shell you can run it by wrapping it into

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

46:

$ java -jar $JETTY_HOME/start.jar

The

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 option is quite flexible and below you can find a few examples of how to use it to avoid forking a second JVM, or generating scripts or creating an arguments file that can be passed to [a possibly alternative]

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

48 executable.

To display the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

48 executable used to start Jetty:

$ java -jar $JETTY_HOME/start.jar

To display the JVM options:

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

To display the JVM class-path:

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

To display the JVM class-path and module-path, if you want to with the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option:

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

To display the JVM main class:

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

The main class is typically Jetty’s

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

51 class that accepts, as program arguments, a list of properties and a list of Jetty XML files to process. The Jetty XML files compose together the Jetty components that are then configured with the values from the command line properties.

To display the program arguments passed to the main class:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

Note how the program arguments are a list of properties in the form

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

52 and a list of Jetty XML files.

The various parts of the full JVM command line can be combined to leverage the arguments file feature [that is, specify the JVM options in a file rather than on the command line] that is built-in in the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

48 executable:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

Using

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

54 can be used to avoid that the Jetty start mechanism forks a second JVM when using modules that require forking:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

The output of different

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

33 executions can be creatively combined in a shell script:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

After you have configured the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory, as explained in , you can start Jetty as a standalone server.

In the start mode, the Jetty start mechanism computes a JVM command line with JVM options, system properties, class-path, module-path, main class and program arguments, and then executes it, forking a new JVM if necessary.

The Jetty start mechanism performs these steps:

Loads all the Jetty modules files [that have extension $ java -jar $JETTY_HOME/start.jar
from the java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 58 subdirectory of each configuration source directory [see for the list of configuration sources]. In this way, a Jetty module graph can be built in memory, where the module dependencies form the edges of the graph and each node contains the metadata information declared by each module [for example, the libraries that it needs, the XML files to process, and so on], in preparation for the next step.
Reads the Jetty module configuration files [that have extension $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE
from the $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 73 subdirectory of each configuration source directory and from the command line. This step produces a list of enabled modules; for each enabled module all its dependencies are transitively resolved by navigating the graph built in the previous steps.
Processes the list of enabled [explicitly and transitively] modules, gathering the list of libraries to add to the class-path, the JPMS directives to add to the command line, the properties and XML files to add as program arguments, etc., so that a full JVM command line can be generated.
Executes the command line, either in-JVM or by forking a second JVM [if the java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
35 option is present or implied by other options such as
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 36], and waits for the JVM, or the forked JVM, to exit.

When the Jetty server is started in-JVM, the server class-path gathered by processing the enabled modules is organized in a

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

63, the Jetty Start ClassLoader, that is a child of the System ClassLoader:

The System ClassLoader only has

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

56 in its class-path, since the JVM was started with

$ java -jar $JETTY_HOME/start.jar

60. The Jetty Start ClassLoader has in its class-path the

$ java -jar $JETTY_HOME/start.jar

02 files gathered by processing the enabled modules, typically from

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

67, but possibly also from

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

68 if custom modules extend the server class-path with their own

$ java -jar $JETTY_HOME/start.jar

02 files.

When the Jetty server is started in a forked JVM, there will be two JVMs: one started by you with

$ java -jar $JETTY_HOME/start.jar

60 and one forked by the Jetty start mechanism. In the forked JVM, the System ClassLoader has the server class-path and/or module-path in its class-path, since the forked JVM is started with

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

71:

It is worth mentioning that there are two standard Jetty modules that allow you to easily add entries to the Jetty server class-path:

The , which adds the java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
73 directory to the server class-path. This is useful if you have third party libraries that lookup resources from the class-path: just put those resources in the
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
74 directory. Logging libraries often perform class-path lookup of their configuration files [for example,
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
75,
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
76,
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
77, and
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
78], so
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 74 is the ideal place to add those files.
The the java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
80 module, that adds all the $ java -jar $JETTY_HOME/start.jar 02 files under the
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
82 directory, and subdirectories recursively, to the server class-path. On one hand, the
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
80 module provides a handy place to put third party libraries and their dependencies; on the other hand, the
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
82 directory may become a confused mixture of many $ java -jar $JETTY_HOME/start.jar 02 files from different third party libraries. Prefer to group third party libraries and their dependencies into their own directories using , or at least group them into
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
82 subdirectories such as
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist
87 or
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 88.

The Jetty start mechanism eventually invokes, by default, main class

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

89, passing properties and as program arguments.

The Jetty XML files are nothing more than Java code in XML format.

The XML files are processed to instantiate Jetty components such as

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

90 or

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

91. The components are then assembled together to provide the configured Jetty features.

The Jetty XML files are parametrized using properties, and a property is just a name/value pair.

This parametrization of the XML files allows an XML file that resides in

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

92 to declare a property such as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

83, and allow this property to be set in a

$ java -jar $JETTY_HOME/start.jar

95 file, so that you don’t need to change the XML files in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33, but only change files in your

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34.

You can write your own with your own Jetty XML files, and your own properties, to further customize Jetty.

Jetty modules are proper JPMS modules: each Jetty module has a

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

97 file. This makes possible to run Jetty from the module-path, rather than the class-path.

To start Jetty on the module-path rather than the class-path, it is enough to add the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option to the command line, for example:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

The

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option implies the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

35 option.

When running on the module-path using the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option, the Jetty start mechanism will fork a second JVM passing it the right JVM options to run on the module-path.

Therefore, you will have two JVMs running: one that runs

$ java -jar $JETTY_HOME/start.jar --list-modules=*

02 and one that runs Jetty on the module-path.

Forking a second JVM may be avoided as explained in .

When Jetty is started in JPMS mode, all JPMS modules in the module-path are added to the set of JPMS root modules through the JVM option

$ java -jar $JETTY_HOME/start.jar --list-modules=*

03.

For a

$ java -jar $JETTY_HOME/start.jar

02 file that is not a JPMS module, but is on the module-path, the JVM will assume internally it is an automatic JPMS module, with a JPMS module name derived from the

$ java -jar $JETTY_HOME/start.jar

02 file name.

Rather than adding the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option to the command line, you can use a custom Jetty module to centralize your JPMS configuration, where you can specify additional JPMS directives.

Create the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

07 file:

jpms.mod

$ java -jar $JETTY_HOME/start.jar --list-modules=*

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

08 section with

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 is equivalent to passing the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

36 option to the command line [see also ].

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

11 section allows you to specify additional JPMS configuration, for example additional

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

80 options, or

$ java -jar $JETTY_HOME/start.jar --list-modules=*

13 options, etc. [see also ].

Then enable it:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

Now you can start Jetty without extra command line options, and it will start in JPMS mode because you have enabled the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

14 module.

Web applications may need additional services from the Servlet Container, such as JDBC

$ java -jar $JETTY_HOME/start.jar --list-modules=*

15 references or JTA

$ java -jar $JETTY_HOME/start.jar --list-modules=*

16 references.

For example, for JDBC it is typical to store, in JNDI, a reference to the connection pool’s

$ java -jar $JETTY_HOME/start.jar --list-modules=*

15 or directly a reference to the JDBC driver’s

$ java -jar $JETTY_HOME/start.jar --list-modules=*

15 [for example,

$ java -jar $JETTY_HOME/start.jar --list-modules=*

19]. Jetty needs to be able to instantiate those classes and therefore needs to be able to load those classes and all their super-classes, among which includes

$ java -jar $JETTY_HOME/start.jar --list-modules=*

20.

When Jetty runs on the class-path, this is easily achieved by using a as explained in .

However, when running on the module-path, things are quite different.

When Jetty tries to load, for example, class

$ java -jar $JETTY_HOME/start.jar --list-modules=*

19, it must be in a JPMS module that is resolved in the run-time module graph. Furthermore, any dependency, for example classes from the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

22 JPMS module, must also be in a module present in the resolved module graph.

Thanks to the fact that when Jetty starts in JPMS mode the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

03 option is added to the JVM command line, every

$ java -jar $JETTY_HOME/start.jar

02 file in the module-path is also present in the module graph.

There are now two cases for the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

25 file: either it is a proper JPMS module, or it is an automatic JPMS module [either an explicit automatic JPMS module with the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

26 attribute in the manifest, or an implicit automatic JPMS module whose name is derived from the

$ java -jar $JETTY_HOME/start.jar

02 file name].

If the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

25 file is a proper JPMS module, then there is nothing more that you should do: the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

25 file is in the module-path, and all the modules in the module-path are in the module graph, and any dependency declared in the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

97 will be added to the module graph.

Otherwise,

$ java -jar $JETTY_HOME/start.jar --list-modules=*

25 file is an automatic module, and will likely have a dependency on the JDK-bundled

$ java -jar $JETTY_HOME/start.jar --list-modules=*

22 JPMS module. However, the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

22 JPMS module is not in the module graph, because automatic modules do not have a way to declare their dependencies.

For this reason, you have to manually add the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

22 dependency to the module graph. Using the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

35 introduced in as an example, modify your custom module in the following way:

postgresql.mod

$ java -jar $JETTY_HOME/start.jar --list-modules=*

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

11 section is only used when Jetty is started on the module-path.

When Jetty is started, the Jetty components that you have configured by enabling Jetty modules are assembled and started.

If you have started Jetty from a terminal, you can exit the Jetty JVM by hitting Ctrl+C on the same terminal.

Similarly, from a different terminal, you can exit the Jetty JVM using

$ java -jar $JETTY_HOME/start.jar --list-modules=*

37 or

$ java -jar $JETTY_HOME/start.jar --list-modules=*

38.

In the three cases above, the JVM is exited, but by default Jetty components are not stopped. If you want to stop the Jetty components, to stop Jetty more gracefully, you can start Jetty with this property:

$ java -jar $JETTY_HOME/start.jar --list-modules=*

This property can also be set in

$ java -jar $JETTY_HOME/start.jar --list-modules=*

39 so that it is persistently configured across Jetty restarts [see also ].

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

41 property configures a JVM shutdown hook that is run, stopping the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 instance, when the JVM exits.

Obviously, the JVM can also be stopped with

$ java -jar $JETTY_HOME/start.jar --list-modules=*

43 that exits the process abruptly without running the JVM shutdown hooks.

You can configure a Jetty server so that it can be stopped by remote clients using a command sent through a TCP socket.

You can start Jetty with the following properties:

$ java -jar $JETTY_HOME/start.jar --list-modules= 44, the host name Jetty will bind to listen for stop commands. Defaults to $ java -jar $JETTY_HOME/start.jar --list-modules= 45 which means that the stop command can be issued only clients that run on the same host as Jetty.
$ java -jar $JETTY_HOME/start.jar --list-modules= 46, the port number Jetty will listen to for stop commands. Defaults to $ java -jar $JETTY_HOME/start.jar --list-modules= 47, which means that Jetty will not listen to any port.
$ java -jar $JETTY_HOME/start.jar --list-modules=* 48, the password to verify when a stop command is received. Defaults to a password that is randomly generated and printed when Jetty starts.

$ java -jar $JETTY_HOME/start.jar --add-modules=http

In the example above, Jetty is started with just the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

46 property, and the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

48 is printed on the terminal when Jetty starts.

You can choose your own

$ java -jar $JETTY_HOME/start.jar --list-modules=*

48, but make sure it’s a strong password.

A remote client can now use the Jetty start mechanism to stop the remote Jetty server:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

Note the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

52 command along with the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

46 and

$ java -jar $JETTY_HOME/start.jar --list-modules=*

48 properties. The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

48 must be the same as the one of remote Jetty server, either the one you chose, or the one printed on the terminal when Jetty starts.

Remote clients can wait for the remote Jetty server to shut down by specifying the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

56 property with the number of seconds to wait:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

If the time specified elapses, without the confirmation that the remote Jetty server stopped, then the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

52 command exits with a non-zero return code.

The steps performed by the Jetty start mechanism are logged by the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

58 class, that outputs directly, by default, to

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59.

This is necessary to avoid that the Jetty start mechanism depend on logging libraries that may clash with those defined by Jetty logging modules, when Jetty is started in-VM.

This section is about the logging performed by the Jetty start mechanism before it configures and starts Jetty. See the for information about logging when Jetty starts.

You can enable DEBUG level logging with the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

60 command line option, for both the tool and start modes:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

You can send the start log output to a file, by default relative to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, with the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

62 option:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

This is useful for capturing startup issues where the Jetty-specific logger has not yet kicked in due to a possible startup configuration error.

$ java -jar $JETTY_HOME/start.jar --add-modules=http

A Jetty module provides one or more Java components that work together to implement one or more features. Such features could be listening for clear-text HTTP/1.1 requests, exposing Jetty components to JMX, provide hot-deployment of web applications, etc.

Every Jetty feature is provided by a Jetty module.

A Jetty module is defined in a

$ java -jar $JETTY_HOME/start.jar --list-modules=*

63 file, where

$ java -jar $JETTY_HOME/start.jar --list-modules=*

64 is the module name [see also the ].

Jetty module files are read from the typical , under the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

58 subdirectory; from higher priority to lower priority:

The $ java -jar $JETTY_HOME/start.jar 67 directory.
If a directory is specified with the
$ java -jar $JETTY_HOME/start.jar 63 option, its
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 58 subdirectory.
The $ java -jar $JETTY_HOME/start.jar 68 directory.

The standard Jetty modules that Jetty provides out-of-the-box are under

$ java -jar $JETTY_HOME/start.jar

68.

A Jetty module has a unique name. The module name is by default derived from the file name, so module file

$ java -jar $JETTY_HOME/start.jar --list-modules=*

71 identifies a module named

$ java -jar $JETTY_HOME/start.jar --list-modules=*

72.

However, a module file may specify a directive for a virtual module, so that many modules may provide a different implementation for the same feature.

For example, among the standard modules provided by Jetty, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module depends on the

$ java -jar $JETTY_HOME/start.jar

20 module, but there is no correspondent

$ java -jar $JETTY_HOME/start.jar --list-modules=*

75 file.

However, the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

76 file has, among others, this section:

logging-jetty.mod

$ java -jar $JETTY_HOME/start.jar --add-modules=http

This section means that the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

76 file provides the virtual module

$ java -jar $JETTY_HOME/start.jar

20, and it is the default provider.

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

79 file has a similar section:

If there are no enabled modules that provide the

$ java -jar $JETTY_HOME/start.jar

20 virtual module, either explicitly or transitively, then the default provider is used, in this case

$ java -jar $JETTY_HOME/start.jar --list-modules=*

76.

Otherwise, a module that provides the

$ java -jar $JETTY_HOME/start.jar

20 virtual module is explicitly or transitively enabled, and the default provider is not used.

A Jetty module may provide one or more Java components that implement a feature. These Java components are nothing more than regular Java classes that are instantiated and configured via files.

The Jetty XML file of a Jetty module may instantiate and assemble together its own components, or reference existing components from other Jetty modules to enhance or reconfigure them.

The Jetty module’s XML files are read from the typical , under the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

83 subdirectory; from higher priority to lower priority:

The $ java -jar $JETTY_HOME/start.jar --list-modules=* 84 directory.
If a directory is specified with the $ java -jar $JETTY_HOME/start.jar 63 option, its $ java -jar $JETTY_HOME/start.jar --list-modules=* 83 subdirectory.
The java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 92 directory.

The standard Jetty modules XML files that Jetty provides out-of-the-box are under

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

92.

For example, a Jetty XML file that allocates Jetty’s

$ java -jar $JETTY_HOME/start.jar --list-modules=*

89 could be as simple as:

jetty-threadpool.xml

$ java -jar $JETTY_HOME/start.jar --add-modules=http

Note how the Jetty XML file above is allocating [with the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

90 element] a

$ java -jar $JETTY_HOME/start.jar --list-modules=*

89 instance, giving it the unique

$ java -jar $JETTY_HOME/start.jar --list-modules=*

92 of

$ java -jar $JETTY_HOME/start.jar --list-modules=*

93 [so that other modules can reference it, if they need to]. It is then calling the setter method

$ java -jar $JETTY_HOME/start.jar --list-modules=*

94 with the value defined by the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

95; if the property value is not defined, it will have the default value of

$ java -jar $JETTY_HOME/start.jar --list-modules=*

96.

This is nothing more than Java code in XML format with configurable properties support that can be leveraged by the .

The Jetty module’s XML files make easy to instantiate and assemble Java components [just write the equivalent Java code in XML format], and make easy to configure them by declaring module properties that can be easily customized elsewhere [for example, in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 files as described in , or on the command line as described in ].

Remember that the standard Jetty XML files in

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

92 should not be modified.

Even if you need to modify a standard Jetty component, write a new Jetty XML file, save it under

$ java -jar $JETTY_HOME/start.jar --list-modules=*

84, and create a so that it gets processed when Jetty starts.

A Jetty module property is declared in the via the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

00 element. Modules properties are used to parametrize Jetty components so that you can customize their values when Jetty starts, rather than hard-coding it in the XML files.

You can declare your own properties, but the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

01 namespace is reserved.

A module property can be given a value in a Jetty module

$ java -jar $JETTY_HOME/start.jar --list-modules=*

08 section [see ], in a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 file as described in , or on the command line as described in .

The syntax to specify a property value is the following:

Sets the property value unconditionally.

Appends the value to the existing value. This is useful to append a value to properties that accept a comma separated list of values, for example:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

Sets the property value only if it is not already set. This is useful to define default values, for example for "version" properties, where the "version" property can be explicitly configured to a newer version, but if it is not explicitly configured it will have a default version [see also ]. For example:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

Lines that start with

$ java -jar $JETTY_HOME/start.jar --add-modules=http

04 are comments.

A list of words that characterize the module.

Modules that have the same tags will be shown by the Jetty start mechanism when using the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

05 command.

A module name with an optional

$ java -jar $JETTY_HOME/start.jar --add-modules=http

06 specifier.

As explained in the , there can be many module files each providing a different implementation for the same feature.

The format is:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

where the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

07 part is optional and specifies that the module is the default provider.

A list of module names that this module depends on.

For example, the standard module

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 depends on module

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64. Enabling the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module also enables, transitively, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module, since the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module cannot work without the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module; when the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module is transitively enabled, the modules it depends on will be transitively enabled, and so on recursively.

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

15 directive establishes a partial order relationship among modules so that enabled modules can be sorted and organized in a graph. Circular dependencies are not allowed.

The order of the enabled modules is used to determine the processing of the configuration, for example the order of processing of the section, the order of processing of XML files defined in the section, etc.

This directive indicates that this module is ordered after the listed module names, if they are enabled.

For example, module

$ java -jar $JETTY_HOME/start.jar

22 is

$ java -jar $JETTY_HOME/start.jar --add-modules=http

17 module

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18. Enabling the

$ java -jar $JETTY_HOME/start.jar

22 module does not enable the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18 module.

However, if the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18 module is enabled [explicitly or transitively], then the

$ java -jar $JETTY_HOME/start.jar

22 module is after the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18 module. In this way, you are guaranteed that the

$ java -jar $JETTY_HOME/start.jar

22 module is processed after the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18 module.

This directive indicates that this module is ordered before the listed module names, if they are enabled.

One use of this directive is to create a prerequisite module without the need to modify the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

26 directive of an existing module. For example, to create a custom

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

90 subclass instance to be used by the standard

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module, without modifying the existing

$ java -jar $JETTY_HOME/start.jar --add-modules=http

29 file nor the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

30 file that it uses. This can be achieved by creating the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

31 :

custom-server.mod

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

32 file is the following:

custom-server.xml

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The presence of the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

33 directive in

$ java -jar $JETTY_HOME/start.jar --add-modules=http

34 causes the processing of the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

32 file to happen before the processing of the standard

$ java -jar $JETTY_HOME/start.jar --add-modules=http

30 file referenced by the standard

$ java -jar $JETTY_HOME/start.jar --add-modules=http

29 Jetty module.

Thus, the instance assigned to the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 identifier is your custom

$ java -jar $JETTY_HOME/start.jar --add-modules=http

39 instance from the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

32 file; this instance is then used while processing the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

30 file.

A list of paths [directories and/or files] that are necessary for the module, created or resolved when the module is enabled.

Each path may be of the following types:

Path Name

A path name representing a file, or a directory if the path name ends with

$ java -jar $JETTY_HOME/start.jar --add-modules=http

42, such as

$ java -jar $JETTY_HOME/start.jar --add-modules=http

43. The file or directory will be created relative to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, if not already present.

For example:

Maven Artifact

An URI representing a Maven artifact to be downloaded from Maven Central, if not already present. Property expansion is supported.

The format is:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

where

$ java -jar $JETTY_HOME/start.jar --add-modules=http

45 is optional, and

$ java -jar $JETTY_HOME/start.jar --add-modules=http

46 after the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

47 is the path under

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 where the downloaded file should be saved.

For example:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

BaseHome

An URI representing a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

33 resource to be copied in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34, if not already present. URIs of this type are typically only used by standard Jetty modules; custom modules should not need to use it.

The format is:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

For example:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

HTTP URL

$ java -jar $JETTY_HOME/start.jar --add-modules=http

51 or

$ java -jar $JETTY_HOME/start.jar --add-modules=http

52 URL to be downloaded, if not already present.

The format is:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

For example:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

53 section if often used in conjunction with the

$ java -jar $JETTY_HOME/start.jar

76 section.

For example:

$ java -jar $JETTY_HOME/start.jar

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

25 artifact is downloaded from Maven Central, if not already present, into the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory when the module is enabled.

When Jetty starts, the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

57 will be in the server class-path [or module-path].

Jetty XML files are read from the typical , under the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

83 subdirectory. Standard Jetty XML files are under

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

92, while custom Jetty XML files are typically under

$ java -jar $JETTY_HOME/start.jar --list-modules=*

84.

For example:

$ java -jar $JETTY_HOME/start.jar

A list of program arguments to pass to the command line when Jetty is started.

The program arguments may include any command line option [see for the list of command line options], and/or .

A property defined in the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

08 section is available in the

$ java -jar $JETTY_HOME/start.jar

75 module file for property expansion, for example:

$ java -jar $JETTY_HOME/start.jar

In the example above, the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

13 section contains

$ java -jar $JETTY_HOME/start.jar --add-modules=http

64, a reference to property

$ java -jar $JETTY_HOME/start.jar --add-modules=http

65 whose value is defined in the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

08 section. The expression

$ java -jar $JETTY_HOME/start.jar --add-modules=http

67 expands the property replacing the expression with the property value.

See also the for additional examples about the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

08 section.

A list of properties to be copied in the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 file generated when .

The list of properties is derived from the that declare them.

The properties are typically assigned their default value and commented out, so that it is evident which properties have been uncommented and customized with a non-default value.

A list of JVM command line options and/or system properties passed to a forked JVM.

When the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

20 section is present, the JVM running the Jetty start mechanism will fork another JVM, passing the JVM command line options and system properties listed in the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

20 sections of the enabled modules.

This is necessary because JVM options such as

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

14 [that specifies the max JVM heap size] cannot be changed in a running JVM. For an example, see .

You can avoid that the Jetty start mechanism forks the second JVM, as explained in .

A list of JVM command line options related to the Java Module System.

The directives are:

add-modules

Equivalent to the JVM option

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

80. The format is:

$ java -jar $JETTY_HOME/start.jar

where

$ java -jar $JETTY_HOME/start.jar --add-modules=http

74 is a JPMS module name.

patch-module

Equivalent to the JVM option

$ java -jar $JETTY_HOME/start.jar --add-modules=http

75. The format is:

$ java -jar $JETTY_HOME/start.jar

where

$ java -jar $JETTY_HOME/start.jar --add-modules=http

74 is a JPMS module name.

add-opens

Equivalent to the JVM option

$ java -jar $JETTY_HOME/start.jar --list-modules=*

13. The format is:

$ java -jar $JETTY_HOME/start.jar

where

$ java -jar $JETTY_HOME/start.jar --add-modules=http

74 and

$ java -jar $JETTY_HOME/start.jar --add-modules=http

79 are a JPMS module names.

add-exports

Equivalent to the JVM option

$ java -jar $JETTY_HOME/start.jar --add-modules=http

80. The format is:

$ java -jar $JETTY_HOME/start.jar

where

$ java -jar $JETTY_HOME/start.jar --add-modules=http

74 and

$ java -jar $JETTY_HOME/start.jar --add-modules=http

79 are a JPMS module names.

add-reads

Equivalent to the JVM option

$ java -jar $JETTY_HOME/start.jar --add-modules=http

80. The format is:

$ java -jar $JETTY_HOME/start.jar

where

$ java -jar $JETTY_HOME/start.jar --add-modules=http

74 and

$ java -jar $JETTY_HOME/start.jar --add-modules=http

79 are a JPMS module names.

The license under which the module is released.

A Jetty module may be released under a license that is different from Jetty’s, or use libraries that require end-users to accept their licenses in order to be used.

You can put the license text in the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

86 section, and when the Jetty module is enabled the license text will be printed on the terminal, and the user prompted to accept the license. If the user does not accept the license, the module will not be enabled.

For example:

$ java -jar $JETTY_HOME/start.jar

The minimum Jetty version for which this module is valid.

For example, a module may only be valid for Jetty 10 and later, but not for earlier Jetty versions [because it references components that have been introduced in Jetty 10].

For example:

A Jetty module with such a section will only work for Jetty 10.0.x or later.

In addition to the modules that come packaged with Jetty, you can create your own custom modules.

Make sure you have read the if you are not familiar with the concepts used in this section.

Custom modules can be used for a number of reasons — they can extend Jetty features, or add new features, or make additional libraries available to the server, etc.

The standard Jetty modules typically come with a number of configurable properties that can be easily customized without the need of writing a custom module.

However, there may be cases where the customization is more complex than a simple property, and a custom module is necessary.

For example, let’s assume that you want to modify the order of the TLS cipher suites offered by the server when a client connects, using the OpenSSL cipher list format.

The Jetty class that handles the TLS configuration is

$ java -jar $JETTY_HOME/start.jar --add-modules=http

87, and it already has a method

$ java -jar $JETTY_HOME/start.jar --add-modules=http

88; however, you need to pass your custom implementation, which cannot be represented with a simple module property.

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

87 component is already allocated by the standard Jetty module

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90, so what you need to do is the following:

Write the custom cipher $ java -jar $JETTY_HOME/start.jar --add-modules=http 91 and package it into a $ java -jar $JETTY_HOME/start.jar 02 file [exercise left to reader].
Write a custom Jetty XML file that calls the $ java -jar $JETTY_HOME/start.jar --add-modules=http 93 method.
Write a custom Jetty module file that depends on the standard $ java -jar $JETTY_HOME/start.jar --add-modules=http 90 module.

Start with the custom Jetty XML file,

$ java -jar $JETTY_HOME/start.jar --add-modules=http

95:

custom-ssl.xml

$ java -jar $JETTY_HOME/start.jar

1 Reference the existing

$ java -jar $JETTY_HOME/start.jar --add-modules=http

87 object created by the standard

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 module using its

$ java -jar $JETTY_HOME/start.jar --list-modules=*

92. 2 Call the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

99 method. 3 Instantiate your custom cipher comparator. 4 Pass to the constructor the ordering string in OpenSSL format, reading it from the module property

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

00.

The cipher list used above may not be secure — it’s just an example.

Then write your custom module in the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

01 file:

custom-ssl.mod

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 A tag that characterizes this custom module [see ]. 2 This custom module depends on the standard

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 module. 3 The custom cipher comparator class is compiled and packaged into this

$ java -jar $JETTY_HOME/start.jar

02 file. 4 The custom Jetty XML file from above. 5 The text that will be copied in the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

04 file when this custom module will be enabled.

Now you can the custom module with the following command issued from the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The command above will produce the following

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory structure:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

In the custom XML file you have used a custom module property to parametrize your custom cipher comparator. This custom module property was then referenced in the

$ java -jar $JETTY_HOME/start.jar

74 section of the custom module file, so that when the custom module is enabled, a correspondent

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

04 file is created.

In this way, updating the cipher list won’t require you to update the XML file, but just the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

04 file.

In the cases where you need to enhance Jetty with a custom functionality, you can write a new Jetty module that provides it.

For example, let’s assume that you need to add a custom auditing component that integrates with the auditing tools used by your company. This custom auditing component should measure the HTTP request processing times and record them [how they are recorded is irrelevant here — could be in a local log file or sent via network to an external service].

The Jetty libraries already provide a way to measure HTTP request processing times via : you write a custom

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

10 subclass that overrides the methods corresponding to the events you are interested in.

Write the auditing component and package it into a $ java -jar $JETTY_HOME/start.jar 02 file.
Write a custom Jetty XML file that wires the auditing component to the INFO : mkdir ${jetty.base}/start.d INFO : server transitively enabled, ini template available with --add-modules=server INFO : logging-jetty transitively enabled INFO : http initialized in ${jetty.base}/start.d/http.ini INFO : resources transitively enabled INFO : threadpool transitively enabled, ini template available with --add-modules=threadpool INFO : logging/slf4j dynamic dependency of logging-jetty INFO : bytebufferpool transitively enabled, ini template available with --add-modules=bytebufferpool INFO : mkdir ${jetty.base}/resources INFO : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties INFO : Base directory was modified 13 tree.
Write a custom Jetty module file that puts everything together.

Let’s start with the auditing component, sketched below:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Let’s assume that this class is compiled and packaged into

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

14, and that it has a dependency on

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

15. Both

$ java -jar $JETTY_HOME/start.jar

02 files will be put in the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory.

Next, let’s write the Jetty XML file that wires the auditing component to the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

18,

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

19:

acme-audit.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 Reference

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 instance. 2 Call

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

21 on the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 so that the auditing component will be inserted just after the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 and just before its child

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

13. 3 Instantiate the auditing component. 4 Configure the auditing component with a property.

The last step is to create the custom Jetty module file for the auditing component,

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

25:

acme-audit.mod

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 The tags that characterize this custom module [see ]. 2 This custom module depends on the standard

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module. 3 The

$ java -jar $JETTY_HOME/start.jar

02 files that contains the custom auditing component, and its dependencies. 4 The custom Jetty XML file from above. 5 The text that will be copied in the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

28 file when this custom module will be enabled.

Now you can the custom auditing module with the following command issued from the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The command above will produce the following

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory structure:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Enabling the custom auditing component will create the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

31 module configuration file that you can edit to configure auditing properties.

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

32 module enables support for the ALPN negotiation mechanism of the TLS protocol.

You can configure the list of application protocols negotiated by the ALPN mechanism, as well as the default protocol to use if the ALPN negotiation fails [for example, the client does not support ALPN].

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

34 module allows you to configure the server-wide

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

36 pool. Pooling

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

36s results in less memory usage and less pressure on the Garbage Collector.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

36s are pooled in buckets; each bucket as a capacity that is a multiple of a capacity factor that you can configure. For example, if a request for a

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

36 of capacity 2000 is requested, and the capacity factor is 1024, then the pool will allocate a buffer from the second bucket, of capacity 2048 [1024 * 2].

Applications that need to sustain many concurrent requests — or load spikes — may require many buffers during peak load. These buffers will remain pooled once the system transitions to a lighter load [or becomes idle], and it may be undesirable to retain a lot of memory for an idle system.

It is possible to configure the max heap memory and the max direct memory that the pool retains. Excess buffers will not be pooled and will be eventually garbage collected.

The module file is

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

40:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

This property allows you to cap the max heap memory retained by the pool.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

This property allows you to cap the max direct memory retained by the pool.

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

43 module captures

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

45 and

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59 output and appends it to a rolling file.

The file is rolled every day at the midnight of the configured timezone. Old, rolled files are kept for the number of days specified by the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

47 property.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

This module enables webapp deployment from the

$ java -jar $JETTY_HOME/start.jar

07 directory.

Deployment is managed via a

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 component that watches a directory for changes. See for more information.

TODO

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

51 module provides support for the CORS protocol implemented by browsers when performing cross-origin requests.

This module installs the in the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

13 tree;

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

53 inspects cross-origin requests and adds the relevant CORS response headers.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

53 should be used when an application performs cross-origin requests to your server, to protect from cross-site request forgery attacks.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

This module enables webapp deployment from the

$ java -jar $JETTY_HOME/start.jar

07 directory.

Deployment is managed via a

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 component that watches a directory for changes. See for more information.

Adding files or directories to this monitored directory will cause the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 to deploy them as web applications; updating files already existing in this monitored directory will cause the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 to re-deploy the corresponding web application; removing files in this monitored directory will cause the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 to "undeploy" the corresponding web application. [You can find a more detailed discussion of these rules in the section.]

Multiple versions of this module exist [

$ java -jar $JETTY_HOME/start.jar

to support each Jakarta EE platform’s version of the Java Servlet specification. Jetty’s configuration properties are nearly identical across these versions; the configuration properties for the

$ java -jar $JETTY_HOME/start.jar

04 Jetty module are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The name of the monitored directory.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The scan period in seconds, that is how frequently the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 wakes up to scan the monitored directory for changes. Setting

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

68 disabled hot deployment so that only static deployment will be possible [see also for more information].

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module provides the clear-text connector and support for the clear-text HTTP/1.1 protocol, and depends on the .

The module properties to configure the clear-text connector are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The network port that Jetty listens to for clear-text HTTP/1.1 connections — default

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

66.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The amount of time a connection can be idle [i.e. no bytes received and no bytes sent] until the server decides to close it to save resources — default

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

75 seconds.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The number of threads that compete to accept connections — default 1. Use -1 to let the accept heuristic decides the value; the current heuristic calculates a value based on the number of cores]. Refer to for more information about acceptor threads.

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

The number of NIO selectors [with an associated thread] that manage connections — default -1 [i.e. a select heuristic decides the value; the current heuristic calculates a value based on the number of cores].

Accepting connections from remote clients may be configured as a blocking operation, or a non-blocking operation.

When accepting connections is configured as a blocking operation [the number of acceptors is greater than zero], a thread is blocked in the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

78 call until a connection is accepted, and other acceptor threads [if any] are blocked on the lock acquired by the accepting thread just before the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

78 call.

When the accepting thread accepts a connection, it performs a little processing of the just accepted connection, before forwarding it to other components.

During this little processing other connections may be established; if there is only one accepting thread, the newly established connections are waiting for the accepting thread to finish the processing of the previously accepted connection and call again

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

78.

Servers that manage a very high number of connections that may [naturally] come and go, or that handle inefficient protocols that open and close connections very frequently [such as HTTP/1.0] may benefit of an increased number of acceptor threads, so that when one acceptor thread processes a just accepted connection, another acceptor thread can immediately take over accepting connections.

When accepting connections is configured as a non-blocking operation [the number of acceptors is zero], then the server socket is set in non-blocking mode and added to a NIO selector. In this way, no dedicated acceptor threads exist: the work of accepting connections is performed by the selector thread.

Performing a NIO

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

81 call is a blocking operation, where the selecting thread is blocked in the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

81 call until at least one connection is ready to be processed for an I/O operation. There are 4 I/O operations: ready to be accepted, ready to be connected, ready to be read and ready to be written.

A single NIO selector can manage thousands of connections, with the assumption that not many of them will be ready at the same time.

For a single NIO selector, the ratio between the average number of selected connections over the total number of connections for every

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

81 call depends heavily on the protocol but also on the application.

Multiplexed TCP protocols such as HTTP/2 tend to be busier than duplex protocols such as HTTP/1.1, leading to a higher ratio.

REST applications that exchange many little JSON messages tend to be busier than file server applications, leading to a higher ratio.

The higher the ratio, the higher the number of selectors you want to have, compatibly with the number of cores — there is no point in having 64 selector threads on a single core hardware.

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18 module enables support for the secure HTTP/2 protocol.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

86 property controls the number of "bad" or "unnecessary" frames that a client may send before the server closes the connection [with code ] to avoid a denial of service.

For example, an attacker may send empty

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

88 frames to a server in a tight loop. While the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

88 frames don’t change the server configuration and each of them is somehow harmless, the server will be very busy processing them because they are sent by the attacker one after the other, causing a CPU spike and eventually a denial of service [as all CPUs will be busy processing empty

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

88 frames].

The same attack may be performed with

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

91 frames, empty

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

92 frames,

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

93 frames, etc.

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

94 module enables support for the clear-text HTTP/2 protocol.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

86 property controls the number of "bad" or "unnecessary" frames that a client may send before the server closes the connection [with code ] to avoid a denial of service.

For example, an attacker may send empty

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

88 frames to a server in a tight loop. While the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

88 frames].

The same attack may be performed with

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

91 frames, empty

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

92 frames,

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

93 frames, etc.

The

$ java -jar $JETTY_HOME/start.jar

04 module enables support for the HTTP/3 protocol.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar

06 module provides support for processing the

$ java -jar $JETTY_HOME/start.jar

08 HTTP header [defined in RFC 7239] and the now obsoleted

$ java -jar $JETTY_HOME/start.jar

09 HTTP headers.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar

22 module provides the HTTP/1.1 protocol to the .

The module file is

$ java -jar $JETTY_HOME/start.jar

13:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

This module enables deployment of Java Servlet web applications.

The

$ java -jar $JETTY_HOME/start.jar

15 module provides remote access to JMX clients.

The module properties to configure remote JMX connector are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The system property

$ java -jar $JETTY_HOME/start.jar

17 is specified with the usual notation, prepending a

$ java -jar $JETTY_HOME/start.jar

18 in front of the system property name.

The system property

$ java -jar $JETTY_HOME/start.jar

17 is uncommented because it is necessary in the default configuration — most systems do not have the local name resolution configured properly for remote access.

As an example, in a Linux machine named

$ java -jar $JETTY_HOME/start.jar

20, the

$ java -jar $JETTY_HOME/start.jar

21 file may contain these entries:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

If the system property

$ java -jar $JETTY_HOME/start.jar

17 is not specified, the RMI implementation uses the host name

$ java -jar $JETTY_HOME/start.jar

20 to figure out the IP address to store in the RMI stub, in this case

$ java -jar $JETTY_HOME/start.jar

24. However, we the RMI server is configured to bind to

$ java -jar $JETTY_HOME/start.jar

25, i.e.

$ java -jar $JETTY_HOME/start.jar --list-modules=*

45.

If the system property

$ java -jar $JETTY_HOME/start.jar

17 is not specified, the RMI client will try to connect to

$ java -jar $JETTY_HOME/start.jar

24 [because that’s what in the RMI stub] and fail because nothing is listening on that address.

The

$ java -jar $JETTY_HOME/start.jar

29 module provides HTTP request/response logging in the standard NCSA format, or in a custom format of your choice.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The property

$ java -jar $JETTY_HOME/start.jar

31 can be customized using format codes.

Format codes are specified with the syntax

$ java -jar $JETTY_HOME/start.jar

32 as follows:

$ java -jar $JETTY_HOME/start.jar

Optional list of comma separated HTTP status codes which may be preceded by a single "!" to indicate negation. If the status code is not in the list the literal string "-" will be logged instead of the resulting value from the percent code.

$ java -jar $JETTY_HOME/start.jar

Parameter string which may be optional depending on the percent code used.

$ java -jar $JETTY_HOME/start.jar

A one or two character code specified by the table of format codes below.

Table 1. Format Codes Format String Description

The X character.

The percent character.

%{format}a

The address or host name.

Valid format values are: "server", "client", "local", "remote". The format parameter is optional and defaults to "server".

Values "server" and "client" are the logical addresses which can be modified in the request headers, while "local" and "remote" are the physical addresses so may be the addresses of a proxy between the end-user and the server.

%{format}p

The port.

Valid format values are: "server", "client", "local", "remote". The format parameter is optional and defaults to "server".

Values "server" and "client" are the logical ports which can be modified in the request headers, while "local" and "remote" are the physical ports so may be the ports of a proxy between the end-user and the server.

%{CLF}I

The size of request in bytes, excluding HTTP headers.

The parameter is optional. When the parameter value is "CLF" the Common Log Format is used, i.e. a

$ java -jar $JETTY_HOME/start.jar

36 rather than a

$ java -jar $JETTY_HOME/start.jar

37 when no bytes are present.

%{CLF}O

The size of response in bytes, excluding HTTP headers.

The parameter is optional. When the parameter value is "CLF" the Common Log Format is used, i.e. a

$ java -jar $JETTY_HOME/start.jar

36 rather than a

$ java -jar $JETTY_HOME/start.jar

37 when no bytes are present.

%{CLF}S

The bytes transferred [received and sent]. This is the combination of

$ java -jar $JETTY_HOME/start.jar

40 and

$ java -jar $JETTY_HOME/start.jar

41.

The parameter is optional. When the parameter value is "CLF" the Common Log Format is used, i.e. a

$ java -jar $JETTY_HOME/start.jar

36 rather than a

$ java -jar $JETTY_HOME/start.jar

37 when no bytes are present.

%{VARNAME}C

The value of the request cookie VARNAME.

The parameter is optional. Only version 0 cookies are fully supported. When the parameter is missing, all request cookies will be logged.

The time taken to serve the request, in microseconds.

%{VARNAME}e

The value of the environment variable VARNAME.

The file system path of the requested resource.

The name and version of the request protocol, such as "HTTP/1.1".

%{VARNAME}i

The value of the VARNAME request header.

The number of requests handled on a connection.

The initial request on a connection yields a value 0, the first request after the initial on the same connection yields the value 1, the second request on the same connection yields the value 2, etc.

The HTTP request method.

%{VARNAME}o

The value of the VARNAME response header.

The query string, prepended with a ? if a query string exists, otherwise an empty string.

First line of an HTTP/1.1 request [or equivalent information for HTTP/2 or later].

The name of the Handler or Servlet generating the response [if any].

The HTTP response status code.

%{format|timeZone|locale}t

The time at which the request was received.

The parameter is optional and may have the following values: {format}, {format|timeZone} or {format|timeZone|locale}.

$ java -jar $JETTY_HOME/start.jar

Default is e.g. [18/Sep/2011:19:18:28 -0400] where the last number indicates the timezone offset from GMT. Must be in a format supported by the

$ java -jar $JETTY_HOME/start.jar

45 package.

$ java -jar $JETTY_HOME/start.jar

Default is GMT. Must be in a format supported by the

$ java -jar $JETTY_HOME/start.jar

45 package.

$ java -jar $JETTY_HOME/start.jar

Default is the JVM default locale. Must be in a format supported by

$ java -jar $JETTY_HOME/start.jar

49.

%{UNIT}T

The time taken to serve the request.

The parameter UNIT is optional and defaults to "s". The parameter UNIT indicates the unit of time: "s" for seconds, "ms" for milliseconds, "us" for microseconds.

$ java -jar $JETTY_HOME/start.jar

50 is identical to

$ java -jar $JETTY_HOME/start.jar

51.

%{d}u

The remote user if the request was authenticated with servlet authentication.

May be an invalid value if response status code [

$ java -jar $JETTY_HOME/start.jar

is 401 [unauthorized].

The parameter is optional. When the parameter value is "d", deferred authentication will also be checked.

The URL path requested, not including any query string.

The connection status when response is completed:

$ java -jar $JETTY_HOME/start.jar

The connection is aborted before the response completed.

$ java -jar $JETTY_HOME/start.jar

The connection may be kept alive after the response is sent.

$ java -jar $JETTY_HOME/start.jar

The connection will be closed after the response is sent.

%{VARNAME}ti

The value of the VARNAME request trailer.

%{VARNAME}to

The value of the VARNAME response trailer.

This module adds the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

73 directory to the server’s classpath.

A common use-case for this module is to provide resources for third-party libraries via the . For instance, many logging libraries [including Log4j2 and Logback] look for their configuration files on the classpath.

Jetty provides a logging library implementation — enabled via the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

65 module — whose configuration file is

$ java -jar $JETTY_HOME/start.jar

81.

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module provides generic server support, and configures generic HTTP properties that apply to all HTTP protocols, the scheduler properties and the server specific properties.

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module configures the shared parameters for generic HTTP handling, but does not enable any specific network protocol. You have to explicitly enable the protocols you want to support by enabling, for example, the for clear-text HTTP/1.1 support, or the for secure HTTP/2 support, etc.

See also the for more information about the supported protocols.

The module properties to configure generic HTTP properties are listed below. Mostly they frequently apply to HTTP/1, HTTP/2 and HTTP/3, but some parameters are version specific:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ java -jar $JETTY_HOME/start.jar

The header cache is used when parsing HTTP/1 to more efficiently handle fields that are repeated in every request on a connection. If the server does not receive persistent connection or infrequent repeated fields, then there may be a performance gain in reducing the cache size. If large fields are frequently repeated, then a large cache may be beneficial.

$ java -jar $JETTY_HOME/start.jar

It is not uncommon for the network packets containing a request header to arrive before packets that contain the data of any request body. In such cases it may be beneficial for overall performance to delay dispatching the request to be handled until the first data packet arrives, as this may avoid blocking the handling thread. However, if minimum latency for receiving the request without content is important, then this parameter can be set to false.

$ java -jar $JETTY_HOME/start.jar

Whether you want to send the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 header in every HTTP response:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The module properties to configure the Jetty server are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ java -jar $JETTY_HOME/start.jar

Whether to perform a

$ java -jar $JETTY_HOME/start.jar

70 operation after the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 has started. The output of the dump operation is sent to

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59. See also the section for more information.

$ java -jar $JETTY_HOME/start.jar

Whether to perform a

$ java -jar $JETTY_HOME/start.jar

70 operation before the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 stops. The output of the dump operation is sent to

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59. See also the section for more information.

$ java -jar $JETTY_HOME/start.jar --list-modules=*

Whether to call

$ java -jar $JETTY_HOME/start.jar

78 through a JVM shutdown hook when the JVM exits.

The Jetty server strives to keep up with the latest IETF RFCs for compliance with internet specifications, which are periodically updated. When possible, Jetty will support backwards compatibility by providing compliance modes that can be configured to allow violations of the current specifications that may have been allowed in obsoleted specifications. The module properties to configure the Jetty server compliance are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ java -jar $JETTY_HOME/start.jar

Configures the compliance to HTTP specifications. The value could be:

One of the predefined $ java -jar $JETTY_HOME/start.jar 80 constants, such as $ java -jar $JETTY_HOME/start.jar 81 or $ java -jar $JETTY_HOME/start.jar 82. For example: $ java -jar $JETTY_HOME/start.jar 83.
A comma-separated list of violations to allow or forbid, as specified by the method. For example, $ java -jar $JETTY_HOME/start.jar 85 means that the HTTP compliance is that defined by $ java -jar $JETTY_HOME/start.jar 81, but also allows the $ java -jar $JETTY_HOME/start.jar 87, so that requests that have multiple $ java -jar $JETTY_HOME/start.jar 88 headers are accepted [they would be rejected when using just $ java -jar $JETTY_HOME/start.jar 89]. For more information about $ java -jar $JETTY_HOME/start.jar 80 see also .

$ java -jar $JETTY_HOME/start.jar

Configures the compliance to URI specifications. The value could be:

One of the predefined $ java -jar $JETTY_HOME/start.jar 92 constants, such as $ java -jar $JETTY_HOME/start.jar 93 or $ java -jar $JETTY_HOME/start.jar 94. For example: $ java -jar $JETTY_HOME/start.jar 95.
A comma-separated list of violations to allow or forbid, as specified by the method. For example, $ java -jar $JETTY_HOME/start.jar 97 means that the URI compliance is that defined by $ java -jar $JETTY_HOME/start.jar 94, but also does not allow the $ java -jar $JETTY_HOME/start.jar 99, so that requests that have URIs such as $ java -jar $JETTY_HOME/start.jar --add-module=demos 000 [where $ java -jar $JETTY_HOME/start.jar --add-module=demos 001 is the URL-encoded $ java -jar $JETTY_HOME/start.jar --add-modules=http 42 character] are rejected [they would be accepted when using just $ java -jar $JETTY_HOME/start.jar --add-module=demos 003]. For more information about $ java -jar $JETTY_HOME/start.jar 92 see also .

$ java -jar $JETTY_HOME/start.jar --add-module=demos

005

$ java -jar $JETTY_HOME/start.jar --add-module=demos

006

Configures the compliance to HTTP cookie specifications. The value could be:

One of the predefined $ java -jar $JETTY_HOME/start.jar --add-module=demos 007 constants, such as $ java -jar $JETTY_HOME/start.jar --add-module=demos 008. For example: $ java -jar $JETTY_HOME/start.jar --add-module=demos 009.
A comma-separated list of violations to allow or forbid, as specified by the method. For example, $ java -jar $JETTY_HOME/start.jar --add-module=demos 011 means that the cookie compliance is that defined by $ java -jar $JETTY_HOME/start.jar --add-module=demos 008, but also does not allow the $ java -jar $JETTY_HOME/start.jar --add-module=demos 013, so that requests that have cookie headers such as $ java -jar $JETTY_HOME/start.jar --add-module=demos 014 are rejected [they would be accepted when using just $ java -jar $JETTY_HOME/start.jar --add-module=demos 015]. For more information about $ java -jar $JETTY_HOME/start.jar --add-module=demos 007 see also .

The module properties to configure the Jetty server scheduler are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 module provides the secure connector, and allows you to configure the KeyStore properties and the TLS parameters, and depends on the .

The module properties to configure the secure connector are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

020

The network port that Jetty listens to for secure connections — default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

021.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

022

The amount of time a connection can be idle [i.e. no bytes received and no bytes sent] until the server decides to close it to save resources — default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

023 milliseconds.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

024

$ java -jar $JETTY_HOME/start.jar --add-module=demos

025

The module properties to configure the KeyStore and TLS parameters are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

026

The KeyStore path on the file system, either an absolute path or a relative path to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 — defaults to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

028.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

029

The KeyStore password, which you want to explicitly configure. The password may be obfuscated with the .

If you need to configure client certificate authentication, you want to configure one of these properties [they are mutually exclusive]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

030

Whether client certificate authentication should be required.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

031

Whether client certificate authentication should be requested.

If you configure client certificate authentication, you need to configure and distribute a client KeyStore as explained in .

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

032 module provides a periodic scanning of the directory where the KeyStore file resides. When the scanning detects a change to the KeyStore file, the correspondent

$ java -jar $JETTY_HOME/start.jar --add-module=demos

034 component is reloaded with the new KeyStore configuration.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

035 module creates on-the-fly a KeyStore containing a self-signed certificate for domain

$ java -jar $JETTY_HOME/start.jar

25. The KeyStore file is automatically deleted when the JVM exits, and re-created when you restart Jetty, to enforce the fact that it is a test KeyStore that should not be reused if not for testing.

The module file is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

038:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note how properties

$ java -jar $JETTY_HOME/start.jar --add-module=demos

026 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

029 are configured, only if not already set [via the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

041 operator], directly in the module file, rather than in a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

74 file. This is done to avoid that these properties accidentally overwrite a real KeyStore configuration.

The

$ java -jar $JETTY_HOME/start.jar

19 module allows you to configure the server-wide thread pool.

The thread pool creates threads on demand up to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

045, and idles them out if they are not used.

Since Jetty uses the thread pool internally to execute critical tasks, it is not recommended to constrain the thread pool to small values of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

045 with the purpose of limiting HTTP request concurrency, as this could very likely cause a server lockup when Jetty needs to run a critical task but there are no threads available. Start with the default value of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

045, and tune for larger values if needed.

The module properties to configure the thread pool are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Among the configurable properties, the most relevant are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

048

The name prefix to use for the thread names.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

049

Whether the thread pool should dump the whole stack trace of each thread, or just the topmost stack frame — defaults to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

051

The time, in milliseconds, after which an idle thread is released from the pool — defaults to 60000, i.e. 60 seconds.

$ java -jar $JETTY_HOME/start.jar --list-modules=*

The max number of threads pooled by the thread pool — defaults to 200.

If you want to use virtual threads, introduced as a preview feature in Java 19 and Java 20, and become an official feature since Java 21, use the following modules:

The Jetty module for Java 21 or later.
The Jetty module for Java 19 and Java 20.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

053 module allows you to configure the server-wide thread pool, similarly to what you can do with the Jetty module, but also specify to use virtual threads, introduced as an official feature since Java 21.

Only use this module if you are using Java 21 or later. If you are using Java 19 or Java 20, use the Jetty module instead.

Refer to the Jetty module for the general features provided by that Jetty module that also this Jetty module provides.

The module properties to configure the thread pool are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The specific properties to configure virtual threads are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

060

The name prefix to use for the virtual thread names.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

061

Whether virtual threads inherit the values of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

062 variables.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

054 module allows you to configure the server-wide thread pool, similarly to what you can do with the Jetty module, but also specify to use virtual threads, introduced as a preview feature in Java 19 and in Java 20.

Only use this module if you are using Java 19 or Java 20. If you are using Java 21 or later, use the Jetty module instead.

To enable preview features, this module needs to specify the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

18 command line option using the , and as such it will fork another JVM.

Refer to the Jetty module for the general features provided by that Jetty module that also this Jetty module provides.

The module properties to configure the thread pool are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The specific properties to configure virtual threads are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

060

The name prefix to use for the virtual thread names.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

070

Whether virtual threads are allowed to set thread locals.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

061

Whether virtual threads inherit the values of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

062 variables.

This module enables deployment of Java Servlet web applications.

Multiple versions of this module exist [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

to support each Jakarta EE platform’s version of the Java Servlet specification. Jetty’s configuration properties are identical across all versions of this module, and are as follows:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

075 Jetty module creates a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

077 deployed at the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

078 context path which serves files from a directory. By default, the directory created at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

079 is used, but it can be configured from

$ java -jar $JETTY_HOME/start.jar --add-module=demos

080 to anywhere in the filesystem. Note that the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

081 directory may be seen as a hidden directory by the filesystem.

The concept of well-known URIs has been defined in RFC5785. This module can be used for things like the automatic renewal of Let’s Encrypt certificates. See IANA Well-Known URIs for more possible examples of how this can be used.

The module properties are:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Most of the time you want to be able to customize the deployment of your web applications, for example by changing the

$ java -jar $JETTY_HOME/start.jar

14, or by adding JNDI entries, or by configuring virtual hosts, etc.

Jetty supports the deployment of each web application to a specific environment. The available environments are:

Java EE 8 — Supports Servlet 4.0 [and associated specifications] in the $ java -jar $JETTY_HOME/start.jar --add-module=demos 083 packages.
Jakarta EE 9 — Supports Servlet 5.0 [and associated specifications] in the $ java -jar $JETTY_HOME/start.jar --add-module=demos 084 packages.
Jakarta EE 10 — Supports Servlet 6.0 [and associated specifications] in the $ java -jar $JETTY_HOME/start.jar --add-module=demos 084 packages.
Jetty Core — Supports web applications written against the Jetty INFO : mkdir ${jetty.base}/start.d INFO : server transitively enabled, ini template available with --add-modules=server INFO : logging-jetty transitively enabled INFO : http initialized in ${jetty.base}/start.d/http.ini INFO : resources transitively enabled INFO : threadpool transitively enabled, ini template available with --add-modules=threadpool INFO : logging/slf4j dynamic dependency of logging-jetty INFO : bytebufferpool transitively enabled, ini template available with --add-modules=bytebufferpool INFO : mkdir ${jetty.base}/resources INFO : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties INFO : Base directory was modified 13 APIs, without any Servlet dependencies.

This means that you can simultaneously deploy an old Java EE 8 web application, say

$ java -jar $JETTY_HOME/start.jar --add-module=demos

087, alongside a new Jakarta EE 10 web application, say

$ java -jar $JETTY_HOME/start.jar --add-module=demos

088, alongside a web application that only uses the Jetty

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

13 APIs, say

$ java -jar $JETTY_HOME/start.jar --add-module=demos

090.

The customization of the deployment [for example, web application context path, etc.] is performed by processing .

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

091 module contains the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 component that scans the

$ java -jar $JETTY_HOME/start.jar

07 directory for changes, following the deployment rules described in .

For each specific environment there is a specific deploy module that you must enable:

For Java EE 8,
For Java EE 9,
For Java EE 10,
For Jetty Core,

Each of these modules provide the environment specific features, and depend on the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

091 module that provides the scanning features.

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 scans the

$ java -jar $JETTY_HOME/start.jar

07 directory for changes every

$ java -jar $JETTY_HOME/start.jar --add-module=demos

101 seconds, where

$ java -jar $JETTY_HOME/start.jar --add-module=demos

101 is configured via the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

66 property.

By default, the scan interval is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

104 second, which means that hot deployment is enabled: if a file is added/changed/removed from the

$ java -jar $JETTY_HOME/start.jar

07 directory, the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 will notice the change and respectively deploy/redeploy/undeploy the web application.

Setting the scan interval to

$ java -jar $JETTY_HOME/start.jar

37 means that static deployment is enabled, and the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 will not scan the

$ java -jar $JETTY_HOME/start.jar

07 directory for changes. This means that to deploy/redeploy/undeploy a web application you will need to stop and restart Jetty.

The following command line disables hot deployment by specifying the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

66 property on the command line, and therefore only for this particular run:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

To make static deployment persistent, you need to edit the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

091 module configuration file,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

112, uncomment the module property

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

66 and change its value to

$ java -jar $JETTY_HOME/start.jar

37:

deploy.ini

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Adding a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file, a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 directory, a Jetty context XML file or a normal directory to

$ java -jar $JETTY_HOME/start.jar

07 causes the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 to deploy the new web application.

Updating a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file or a Jetty context XML file causes the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 to redeploy the web application, which means that the Jetty context component representing the web application is stopped, then reconfigured, and then restarted.

Removing a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file, a

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 directory, a Jetty context XML file or a normal directory from

$ java -jar $JETTY_HOME/start.jar

07 causes the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 to undeploy the web application, which means that the Jetty context component representing the web application is stopped and removed from the Jetty server.

When a file or directory is added to

$ java -jar $JETTY_HOME/start.jar

07, the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 derives the web application

$ java -jar $JETTY_HOME/start.jar

14 from the file or directory name, with the following rules:

If the directory name is, for example, $ java -jar $JETTY_HOME/start.jar --add-module=demos 128, it is deployed as a standard web application if it contains a $ java -jar $JETTY_HOME/start.jar --add-module=demos 129 subdirectory, otherwise it is deployed as a web application of static content. The $ java -jar $JETTY_HOME/start.jar 14 would be $ java -jar $JETTY_HOME/start.jar --add-module=demos 131 [that is, the web application is reachable at $ java -jar $JETTY_HOME/start.jar --add-module=demos 132].
If the directory name is $ java -jar $JETTY_HOME/start.jar --add-module=demos 133, case-insensitive, the $ java -jar $JETTY_HOME/start.jar 14 is $ java -jar $JETTY_HOME/start.jar --add-modules=http 42 [that is, the web application is reachable at $ java -jar $JETTY_HOME/start.jar --add-module=demos 136].
If the directory name ends with $ java -jar $JETTY_HOME/start.jar --add-module=demos 137, for example $ java -jar $JETTY_HOME/start.jar --add-module=demos 138, it is ignored, although it may be referenced to configure other web applications [for example to store common files].
If the $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 37 file name is, for example, $ java -jar $JETTY_HOME/start.jar --add-module=demos 140, it is deployed as a standard web application with the context path $ java -jar $JETTY_HOME/start.jar --add-module=demos 131 [that is, the web application is reachable at $ java -jar $JETTY_HOME/start.jar --add-module=demos 132].
If the file name is $ java -jar $JETTY_HOME/start.jar --add-module=demos 143, case-insensitive, the $ java -jar $JETTY_HOME/start.jar 14 is $ java -jar $JETTY_HOME/start.jar --add-modules=http 42 [that is, the web application is reachable at $ java -jar $JETTY_HOME/start.jar --add-module=demos 136].
If both the $ java -jar $JETTY_HOME/start.jar --add-module=demos 140 file and the $ java -jar $JETTY_HOME/start.jar --add-module=demos 128 directory exist, only the file is deployed. This allows the directory with the same name to be the $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 37 file unpack location and avoid that the web application is deployed twice.
A named $ java -jar $JETTY_HOME/start.jar --add-module=demos 150 is deployed as a web application by processing the directives contained in the XML file itself, which must set the $ java -jar $JETTY_HOME/start.jar 14, which could be different from the name of the XML file.
If both $ java -jar $JETTY_HOME/start.jar --add-module=demos 150 and $ java -jar $JETTY_HOME/start.jar --add-module=demos 140 exist, only the XML file is deployed. This allows the XML file to reference the $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 37 file and avoid that the web application is deployed twice.

A web application is always deployed to a specific environment, which is either configured for the deployed application or set to the default environment.

If only a single specific deployer module is enabled, for example

$ java -jar $JETTY_HOME/start.jar

04, then it is the default environment and applications will be deployed to it without any additional configuration.

If multiple deployer modules are enabled, then the default environment is:

The most recent Jakarta EE environment of the $ java -jar $JETTY_HOME/start.jar 05 modules that are enabled.
Otherwise, the
$ java -jar $JETTY_HOME/start.jar --add-module=demos 157 environment, if the
INFO : mkdir ${jetty.base}/start.d INFO : server transitively enabled, ini template available with --add-modules=server INFO : logging-jetty transitively enabled INFO : http initialized in ${jetty.base}/start.d/http.ini INFO : resources transitively enabled INFO : threadpool transitively enabled, ini template available with --add-modules=threadpool INFO : logging/slf4j dynamic dependency of logging-jetty INFO : bytebufferpool transitively enabled, ini template available with --add-modules=bytebufferpool INFO : mkdir ${jetty.base}/resources INFO : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties INFO : Base directory was modified 48 module is enabled.
Otherwise, no deployer environment has been enabled, and therefore no application can be deployed.

For example, if

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

48,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

095 and the

$ java -jar $JETTY_HOME/start.jar

04 modules are enabled, then

$ java -jar $JETTY_HOME/start.jar --add-module=demos

162 is the default environment, to which applications will be deployed unless otherwise configured [see below].

To configure a specific environment for an application, you add a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

163 file with the same name of the web application. For example, an application deployed to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

164 is configured with the file

$ java -jar $JETTY_HOME/start.jar --add-module=demos

165, with the following content:

In case of simultaneous multiple deployer environments, it is good practice to always specify the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

163 file for your web applications.

If you do not specify the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

163 file for your web applications, then the deployer for the default environment will be used.

For example, if you have enabled the deployer Jetty module for all Jakarta EE versions, and you deploy an EE 9 web application without the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

163 file, then it will be deployed by the EE 10 deployer, with unspecified results.

This unspecified deployment may not work as the EE 9 web application may use APIs that have been removed in EE 10, causing an error at runtime.

A Jetty context XML file is a that allows you to customize the deployment of web applications.

Recall that the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 component of the Jetty

$ java -jar $JETTY_HOME/start.jar --add-module=demos

091 module to Jetty context XML files over

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 files or directories.

To deploy a web application using a Jetty context XML file, simply place the file in the

$ java -jar $JETTY_HOME/start.jar

07 directory.

A simple Jetty context XML file, for example named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

173 is the following:

wiki.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

174, which is the Jetty component that represents a standard Servlet web application. 2 Specifies the web application

$ java -jar $JETTY_HOME/start.jar

14, which may be different from the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file name. 3 Specifies the file system path of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file.

The Jetty content XML file may be accompanied by a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

163 file that specifies the to use for the deployment:

Refer to for more information about specifying the environment.

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory would look like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file may be placed anywhere in the file system and does not need to be placed in the

$ java -jar $JETTY_HOME/start.jar

07 directory.

If you place both the Jetty context XML file and the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file in the

$ java -jar $JETTY_HOME/start.jar

07 directory, remember that they must have the same file name, for example

$ java -jar $JETTY_HOME/start.jar --add-module=demos

173 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

185, so that the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

50 deploys the web application only once using the Jetty context XML file [and not the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file].

You can use the features of to avoid to hard-code file system paths or other configurations in your Jetty context XML files, for example by using system properties:

wiki.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note how the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file path is now obtained by resolving the system property

$ java -jar $JETTY_HOME/start.jar --add-module=demos

189 that you can specify on the command line when you start Jetty:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

A web application may reference a JNDI entry, such as a JDBC

$ java -jar $JETTY_HOME/start.jar --list-modules=*

15 from the web application

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 file. The JNDI entry must be defined in a , for example a context XML like so:

mywebapp.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

For more information and examples on how to use JNDI in Jetty, refer to the feature section.

Class

$ java -jar $JETTY_HOME/start.jar --add-module=demos

192 is present in the MySQL JDBC driver file,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

193, which must be available on the server’s classpath .

If the class is instead present within the web application, then the JNDI entry must be declared in a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

194 file - see the feature section for more information and examples.

A virtual host is an internet domain name, registered in the Domain Name Server [DNS], for an IP address such that multiple virtual hosts will resolve to the same IP address of a single server instance.

If you have multiple web applications deployed on the same Jetty server, by using virtual hosts you will be able to target a specific web application.

For example, you may have a web application for your business and a web application for your hobbies , both deployed in the same Jetty server. By using virtual hosts, you will be able to have the first web application available at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

195, and the second web application available at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

196.

Another typical case is when you want to use different subdomains for different web application, for example a project website is at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

197 and the project documentation is at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

198.

Virtual hosts can be used with any context that is a subclass of ContextHandler.

Jetty supports the following variants to be specified as virtual host names:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

199

A fully qualified domain name. It is important to list all variants as a site may receive traffic for both

$ java -jar $JETTY_HOME/start.jar --add-module=demos

199 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

201.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

202

A wildcard domain name which will match only one level of arbitrary subdomains. *.foo.com will match www.foo.com and m.foo.com, but not www.other.foo.com.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

203

An IP address may be set as a virtual host to indicate that a web application should handle requests received on the network interface with that IP address for protocols that do not indicate a host name such as HTTP/0.9 or HTTP/1.0.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

204

A Jetty server

$ java -jar $JETTY_HOME/start.jar --add-module=demos

205 name to indicate that a web application should handle requests received on the server

$ java -jar $JETTY_HOME/start.jar --add-module=demos

205 with that name, and therefore received on a specific socket address [either an IP port for

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

18, or a Unix-Domain path for

$ java -jar $JETTY_HOME/start.jar --add-module=demos

208]. A server

$ java -jar $JETTY_HOME/start.jar --add-module=demos

205 name can be set via .

$ java -jar $JETTY_HOME/start.jar --add-module=demos

210

Non-ASCII and IDN domain names can be set as virtual hosts using Puny Code equivalents that may be obtained from a Punycode/IDN converters. For example if the non-ASCII domain name

$ java -jar $JETTY_HOME/start.jar --add-module=demos

210 is given to a browser, then the browser will make a request that uses the domain name

$ java -jar $JETTY_HOME/start.jar --add-module=demos

212, which is the name that should be added as the virtual host name.

If you have a web application

$ java -jar $JETTY_HOME/start.jar --add-module=demos

140 you can configure its virtual hosts in this way:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Your web application will be available at:

$ java -jar $JETTY_HOME/start.jar --add-module=demos 214
$ java -jar $JETTY_HOME/start.jar --add-module=demos 215
$ java -jar $JETTY_HOME/start.jar --add-module=demos 216
$ java -jar $JETTY_HOME/start.jar --add-module=demos 217

You configured the

$ java -jar $JETTY_HOME/start.jar

14 of your web application to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

131.

As such, a request to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

220 will not match your web application because the

$ java -jar $JETTY_HOME/start.jar

14 does not match.

Likewise, a request to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

222 will not match your web application because the virtual host does not match.

If you want to deploy different web applications to the same context path, typically the root context path

$ java -jar $JETTY_HOME/start.jar --add-modules=http

42, you must use virtual hosts to differentiate among web applications.

You have

$ java -jar $JETTY_HOME/start.jar --add-module=demos

224 that you want to deploy at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

195 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

226 that you want to deploy at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

227.

To achieve this, you simply use the same context path of

$ java -jar $JETTY_HOME/start.jar --add-modules=http

42 for each of your webapps, while specifying different virtual hosts for each of your webapps:

domain.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

hobby.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Sometimes it is required to serve different web applications from different socket addresses [either different IP ports, or different Unix-Domain paths], and therefore from different server

$ java -jar $JETTY_HOME/start.jar --add-module=demos

205s.

For example, you want requests to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

136 to be served by one web application, but requests to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

231 to be served by another web application.

This configuration may be useful when Jetty sits behind a load balancer.

In this case, you want to , each with a different name, and then reference the connector name in the web application virtual host configuration:

domain.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

hobby.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Web application

$ java -jar $JETTY_HOME/start.jar --add-module=demos

224 has a virtual host of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

233, where

$ java -jar $JETTY_HOME/start.jar --add-module=demos

234 is the name of a Jetty connector.

Likewise, web application

$ java -jar $JETTY_HOME/start.jar --add-module=demos

226 has a virtual host of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

236, where

$ java -jar $JETTY_HOME/start.jar --add-module=demos

237 is the name of another Jetty connector.

See for further information about how to configure connectors.

By default,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 files are uncompressed and its content extracted in a temporary directory. The web application resources are served by Jetty from the files extracted in the temporary directory, not from the files within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file, for performance reasons.

If you do not want Jetty to extract the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 files, you can disable this feature, for example:

mywebapp.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You can configure an additional

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 that complements the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 file that is present in the web application

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file. This additional

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 is processed after the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191. This allows you to add host specific configuration or server specific configuration without having to extract the web application

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191, modify it, and repackage it in the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file.

mywebapp.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The format of the additional

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 is exactly the same as a standard

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 file, for example:

mywebapp-web.xml

$ java -jar $JETTY_HOME/start.jar --add-module=demos

In the example above, you configured the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

252 Servlet [defined in the web application

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191], adding a host specific

$ java -jar $JETTY_HOME/start.jar --add-module=demos

254 with the IP address of the host.

The Jetty

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 object is the central component that links protocol connectors to web applications.

The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 component is defined by the , that in turn depends on other Jetty modules that provide key functionalities, in particular:

You can configure two types of logging in Jetty: server logging and request logging.

refers to the console output produced by Jetty itself.
refers to the information that Jetty can capture about incoming HTTP requests and responses.

Jetty uses the SLF4J API for its logging. SLF4J is a generic abstraction layer that is supported by many different logging frameworks [or SLF4J bindings].

Jetty provides a default binding via the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

260 Maven artifact, but you can plug in the SLF4J binding provided by other logging frameworks.

Jetty’s server logging is enabled by default with the

$ java -jar $JETTY_HOME/start.jar

20 Jetty module. You typically won’t have to enable the

$ java -jar $JETTY_HOME/start.jar

20 module directly, since it is a transitive dependency of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module, and thus pulled in by many of the most commonly used modules.

The

$ java -jar $JETTY_HOME/start.jar

20 module is a and its default implementation is provided by the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

65 Jetty module, which uses the Jetty SLF4J binding.

Jetty’s default SLF4J binding uses an appender [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

to format a logging message with metadata [like a timestamp] before sending it to

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59. The default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

268 format is:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

where

$ java -jar $JETTY_HOME/start.jar --add-module=demos

269 is a timestamp with the format

$ java -jar $JETTY_HOME/start.jar --add-module=demos

270.

You can configure the appender via a file named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

271, which must be found in the server . When you enable the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

65 module — either directly or by transitive dependency, as in the following example — Jetty automatically generates a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

271 file in

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

74:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

You can specify the following configuration options in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

271:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

276

Sets the logging level for the logger tree based at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

277. You can specify any of the usual SLF4J logging levels —

$ java -jar $JETTY_HOME/start.jar --add-module=demos

278,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

279,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

280 [default],

$ java -jar $JETTY_HOME/start.jar --add-module=demos

281 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

282 — plus two additional levels:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

283 [an alias for

$ java -jar $JETTY_HOME/start.jar --add-module=demos

285 [disables logging entirely]. You can also configure a default logging level for specific loggers, or arbitrary logger trees:

$ java -jar $JETTY_HOME/start.jar --add-module=demos 286 [sets logging level of logger $ java -jar $JETTY_HOME/start.jar --add-module=demos 287 to $ java -jar $JETTY_HOME/start.jar --add-module=demos 279]
$ java -jar $JETTY_HOME/start.jar --add-module=demos 289 [sets logging level of tree $ java -jar $JETTY_HOME/start.jar --add-module=demos 290 to $ java -jar $JETTY_HOME/start.jar --add-module=demos 279]

$ java -jar $JETTY_HOME/start.jar --add-module=demos

292

Specifies whether to hide stack traces for some arbitrary logger tree

$ java -jar $JETTY_HOME/start.jar --add-module=demos

290. The exception type and message are logged normally; only stack traces are hidden. Default value is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050

$ java -jar $JETTY_HOME/start.jar --add-module=demos

295

Specifies whether to condense logger names, so that for example

$ java -jar $JETTY_HOME/start.jar --add-module=demos

296 becomes

$ java -jar $JETTY_HOME/start.jar --add-module=demos

297. Default value is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

299

Specifies the column at which the logging

$ java -jar $JETTY_HOME/start.jar --add-module=demos

300 should be printed. The value

$ java -jar $JETTY_HOME/start.jar

37 specifies no alignment. Default value is

$ java -jar $JETTY_HOME/start.jar

37.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

303

Specifies whether to escape ISO control characters such as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

304 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

305 present in the message. Character

$ java -jar $JETTY_HOME/start.jar --add-module=demos

304 is replaced with

$ java -jar $JETTY_HOME/start.jar --add-module=demos

307 and character

$ java -jar $JETTY_HOME/start.jar --add-module=demos

305 is replaced with

$ java -jar $JETTY_HOME/start.jar --add-modules=http

47; all other ISO control characters are replaced with

$ java -jar $JETTY_HOME/start.jar --add-module=demos

310. Default value is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

312

Specifies the timezone ID [such as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

313, or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

314 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

269 part of the logging line. The empty string specifies the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

317 timezone. Default value is the local timezone.

When using the Jetty SLF4J binding, the logging levels can be dynamically changed via JMX, see for more information.

Logging to

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59 may be fine at development time, but you will typically want to capture logs on disk for later inspection, or if you don’t have a terminal access [for example, if you started Jetty as a service].

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

43 Jetty module allows you to capture what is written to

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

45 and

$ java -jar $JETTY_HOME/start.jar --list-modules=*

59 and write it to a log file. By default,

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

43 logs to a file in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

323 directory.

The

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

43 Jetty module should be used only in conjunction with the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

65 module, as other SLF4J bindings such as LogBack or Log4j2 have their own, more sophisticated, rolling file appenders.

You can use a different SLF4J binding if you are more familiar with other logging libraries, or if you need custom logging appenders. There are a number of out-of-the-box Jetty modules that you can use:

$ java -jar $JETTY_HOME/start.jar --add-module=demos 326, to use the LogBack binding
$ java -jar $JETTY_HOME/start.jar --add-module=demos 327, to use the Log4j2 binding
$ java -jar $JETTY_HOME/start.jar --add-module=demos 328, to use the Log4j1 binding [note that Log4j 1.x is end-of-life]
$ java -jar $JETTY_HOME/start.jar --add-module=demos 329, to use the $ java -jar $JETTY_HOME/start.jar --add-module=demos 330 binding
$ java -jar $JETTY_HOME/start.jar --add-module=demos 331, to use the SLF4J no-operation binding [discards all logging]

To enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

326 module, run:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Since LogBack is released under a license that is different from Jetty’s, you will be prompted to accept the LogBack license. Once you accept the LogBack license, your

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory will have the following structure.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Jetty downloaded the required LogBack

$ java -jar $JETTY_HOME/start.jar

02 files, and created a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

335 file for configuring your LogBack logging. Please refer to the LogBack configuration manual for more information about how to configure LogBack.

To enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

327 module, run:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

After accepting the Log4j2 license, you will have the following directory structure:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Jetty downloaded the required Log4j2

$ java -jar $JETTY_HOME/start.jar

02 files, and created a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

338 file that you can configure to customize your Log4j2 logging.

When you use libraries that provide the features you need [for example, JDBC drivers], it may be possible that those libraries use a different logging framework than SLF4J.

SLF4J provides bridges for legacy logging APIs that allows you to bridge logging from one of these legacy logging frameworks to SLF4J. Once the logging is bridged to SLF4J, you can use Jetty’s or a so that your logging is centralized in one place.

Jetty provides the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

339 module for bridging from

$ java -jar $JETTY_HOME/start.jar --add-module=demos

330 to SLF4J.

The modules

$ java -jar $JETTY_HOME/start.jar --add-module=demos

341 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

342 similarly provide bridges from Jakarta Commons Logging [JCL] and Apache Log4j, respectively; however, these modules are obsolete and should not be used anymore.

For libraries that use

$ java -jar $JETTY_HOME/start.jar --add-module=demos

330 as their logging framework, you can enable Jetty’s

$ java -jar $JETTY_HOME/start.jar --add-module=demos

339 module:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

339 module implies

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

35 and therefore because it needs to provide the system property

$ java -jar $JETTY_HOME/start.jar --add-module=demos

348 [so that

$ java -jar $JETTY_HOME/start.jar --add-module=demos

330 can read the configuration from the specified file], and because it needs to make available on the System ClassLoader the class

$ java -jar $JETTY_HOME/start.jar --add-module=demos

350.

For example, a library that uses

$ java -jar $JETTY_HOME/start.jar --add-module=demos

330 as its logging library is the Postgresql JDBC driver. With the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

339 Jetty module, the logging follows this diagram:

Note how Jetty logs directly to SLF4J, while the Postgresql JDBC driver logs to SLF4J through the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

353. They both arrive to the SLF4J binding, in this case the Jetty SLF4J binding [but could be any other SLF4J binding such as LogBack].

HTTP requests and responses can be logged to provide data that can be later analyzed with other tools, that can provide information such as the most frequently accessed request URIs, the response status codes, the request/response content lengths, geographical information about the clients, etc.

Request logging is enabled by enabling the

$ java -jar $JETTY_HOME/start.jar

29 Jetty module. In the example below, both the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 Jetty module and the

$ java -jar $JETTY_HOME/start.jar

29 module are enabled, so that you can make HTTP requests to the server and have them logged:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

358 file is the Jetty module configuration file that allows you to configure the

$ java -jar $JETTY_HOME/start.jar

29 module, see for more details.

By default the

$ java -jar $JETTY_HOME/start.jar

29 Jetty module produces the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

361, where the pattern

$ java -jar $JETTY_HOME/start.jar --add-module=demos

362 is replaced with the current date, for example

$ java -jar $JETTY_HOME/start.jar --add-module=demos

363.

The format of the request log lines is the result of a format string that uses formatting symbols to log relevant request/response data.

The default format is the NCSA Format extended with referrer data and user-agent data. A typical log line looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The line above [that uses fake values] shows

$ java -jar $JETTY_HOME/start.jar --add-module=demos

364 for the client IP address, a hard-coded

$ java -jar $JETTY_HOME/start.jar

36 for the identity,

$ java -jar $JETTY_HOME/start.jar

36 for the authenticated user name,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

367 for the date and time with timezone,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

368 for the HTTP request line,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

369 for the HTTP response status code,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

370 for the HTTP response content length,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

371 for the referrer and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

372 for the user-agent.

The format string can be customized as described in . Request log files are rolled every day, and retained for customizable number of days, by default 90 days.

When Jetty is behind a load balancer, you want to log the remote client IP address, not the load balancer IP address. Refer to to configure the load balancer and Jetty to retain the remote client IP address information.

Jetty uses thread pooling to efficiently execute tasks that provide Jetty functionalities.

Like any other component, the Jetty thread pool is configured and enabled via the , that is transitively enabled by the which, in turn, is transitively enabled by a protocol module such as the :

$ java -jar $JETTY_HOME/start.jar --add-modules=http

The command above gives you the default configuration for the thread pool.

If you want to explicitly configure the thread pool, it is enough to explicitly specify the module:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

After the command above, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Now you can customize the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

378 file to explicitly configure the thread pool.

Virtual threads have been introduced as a preview feature in Java 19 and Java 20, and have become an official feature since Java 21.

The Jetty module provides support for virtual threads in Java 19 and Java 20, and it is mutually exclusive with the

$ java -jar $JETTY_HOME/start.jar

19 Jetty module.

The Jetty module provides support for virtual threads in Java 21 or later, and it is mutually exclusive with the

$ java -jar $JETTY_HOME/start.jar

19 Jetty module.

If you have already enabled the

$ java -jar $JETTY_HOME/start.jar

19 Jetty module, it is sufficient to remove it by removing the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

384 file.

When using Java 21 or later, you can enable the module:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

After the command above, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Now you can customize the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

387 file to explicitly configure the thread pool and the virtual threads and then start Jetty:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Connectors are the network components through which Jetty accepts incoming network connections.

Each connector listens on a network port and can be configured with

$ java -jar $JETTY_HOME/start.jar --add-module=demos

388 components that understand one or more network protocols.

Understanding a protocol means that the connector is able to interpret incoming network bytes [for example, the bytes that represent an HTTP/1.1 request] and convert them into more abstract objects [for example an

$ java -jar $JETTY_HOME/start.jar --add-module=demos

389 object] that are then processed by applications. Conversely, an abstract object [for example an

$ java -jar $JETTY_HOME/start.jar --add-module=demos

is converted into the correspondent outgoing network bytes [the bytes that represent an HTTP/1.1 response].

Like other Jetty components, connectors are enabled and configured by enabling and configuring the correspondent Jetty module.

Recall that you must always issue the commands to enable Jetty modules from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory, and that the Jetty module configuration files are in the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

38 directory.

You can obtain the list of connector-related modules in this way:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Clear text HTTP/1.1 is enabled with the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 Jetty module with the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

$ java -jar $JETTY_HOME/start.jar --add-module=demos

After having enabled the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 module, the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

81 file is the file that you want to edit to configure network and protocol parameters — for more details see .

Note that the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 Jetty module depends on the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 Jetty module.

Some parameters that you may want to configure are in fact common HTTP parameters that are applied not only for clear-text HTTP/1.1, but also for secure HTTP/1.1 or for clear-text HTTP/2 or for encrypted HTTP/2, or for HTTP/3, and these configuration parameters may be present in the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 module configuration file.

You can force the creation of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

401 file via:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Now the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Now you can edit the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

401 file — for more details see .

Secure HTTP/1.1 is enabled with both the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 and

$ java -jar $JETTY_HOME/start.jar

22 Jetty modules with the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The command above enables the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 module, that provides the secure network connector, the KeyStore configuration and TLS configuration — for more details see . Then, the adds HTTP/1.1 as the protocol secured by TLS.

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory looks like this:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note that the KeyStore file is missing, because you have to provide one with the cryptographic material you want [read to create your own KeyStore]. You need to configure these two properties by editing

$ java -jar $JETTY_HOME/start.jar --add-module=demos

410:

$ java -jar $JETTY_HOME/start.jar --add-module=demos 026
$ java -jar $JETTY_HOME/start.jar --add-module=demos 029

As a quick example, you can enable the , that creates on-the-fly a KeyStore containing a self-signed certificate:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory is now:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Starting Jetty yields:

$ java -jar $JETTY_HOME/start.jar

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note how Jetty is listening on port

$ java -jar $JETTY_HOME/start.jar --add-module=demos

021 for the secure HTTP/1.1 protocol.

If you point your browser at

$ java -jar $JETTY_HOME/start.jar --add-module=demos

416 you will get a warning from the browser about a "potential security risk ahead", or that "your connection is not private", or similar message depending on the browser.

This is normal because the certificate contained in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

417 is self-signed — and as such not signed by a recognized certificate authority — and therefore browsers do not trust it.

HTTP/2 is the successor of the HTTP/1.1 protocol, but it is quite different from HTTP/1.1: where HTTP/1.1 is a duplex, text-based protocol, HTTP/2 is a multiplex, binary protocol.

Because of these fundamental differences, a client and a server need to negotiate what version of the HTTP protocol they speak, based on what versions each side supports.

To ensure maximum compatibility, and reduce the possibility that an intermediary that only understands HTTP/1.1 will close the connection when receiving unrecognized HTTP/2 bytes, HTTP/2 is typically deployed over secure connections, using the TLS protocol to wrap HTTP/2.

Browsers only support secure HTTP/2.

The protocol negotiation is performed by the ALPN TLS extension: the client advertises the list of protocols it can speak, and the server communicates to the client the protocol chosen by the server.

For example, you can have a client that only supports HTTP/1.1 and a server that supports both HTTP/1.1 and HTTP/2:

Nowadays, it’s common that both clients and servers support HTTP/2, so servers prefer HTTP/2 as the protocol to speak:

When you configure a connector with the HTTP/2 protocol, you typically want to also configure the HTTP/1.1 protocol. The reason to configure both protocols is that you typically do not control the clients: for example an old browser that does not support HTTP/2, or a monitoring console that performs requests using HTTP/1.1, or a heartbeat service that performs a single HTTP/1.0 request to verify that the server is alive.

You want to configure secure HTTP/2 when Jetty is exposed directly to browsers, because browsers only support secure HTTP/2.

You may configure clear-text HTTP/2 [mostly for performance reasons] if you offload TLS at a load balancer [for example, HAProxy] or at a reverse proxy [for example, nginx].

You may configure clear-text HTTP/2 [mostly for performance reasons] to call microservices deployed to different Jetty servers [although you may want to use secure HTTP/2 for confidentiality reasons].

When you enable secure HTTP/2 you typically want to enable also secure HTTP/1.1, for backwards compatibility reasons: in this way, old browsers or other clients that do not support HTTP/2 will be able to connect to your server.

You need to enable:

the $ java -jar $JETTY_HOME/start.jar --add-modules=http 90 Jetty module, which provides the secure connector and the KeyStore and TLS configuration
the $ java -jar $JETTY_HOME/start.jar --add-modules=http 18 Jetty module, which adds ALPN handling and adds the HTTP/2 protocol to the secured connector
optionally, the $ java -jar $JETTY_HOME/start.jar 22 Jetty module, which adds the HTTP/1.1 protocol to the secured connector

Use the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

As when enabling the

$ java -jar $JETTY_HOME/start.jar

22 Jetty module, you need a valid KeyStore [read to create your own KeyStore].

As a quick example, you can enable the , that creates on-the-fly a KeyStore containing a self-signed certificate:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Starting Jetty yields:

$ java -jar $JETTY_HOME/start.jar

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note how Jetty is listening on port

$ java -jar $JETTY_HOME/start.jar --add-module=demos

021 and the protocols supported are the sequence

$ java -jar $JETTY_HOME/start.jar --add-module=demos

425.

The [ordered] list of protocols after

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

32 are the application protocols, in the example above

$ java -jar $JETTY_HOME/start.jar --add-module=demos

427.

When a new connection is accepted by the connector, Jetty first interprets the TLS bytes, then it handles the ALPN negotiation knowing that the application protocols are [in order]

$ java -jar $JETTY_HOME/start.jar --add-module=demos

428 and then

$ java -jar $JETTY_HOME/start.jar --add-module=demos

429.

You can customize the list of application protocols and the default protocol to use in case the ALPN negotiation fails by editing the properties.

The HTTP/2 protocol parameters can be configured by editing the properties.

When you enable clear-text HTTP/2 you typically want to enable also clear-text HTTP/1.1, for backwards compatibility reasons and to allow clients to from HTTP/1.1 to HTTP/2.

You need to enable:

the $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 61 Jetty module, which provides the clear-text connector and adds the HTTP/1.1 protocol to the clear-text connector
the INFO : mkdir ${jetty.base}/start.d INFO : server transitively enabled, ini template available with --add-modules=server INFO : logging-jetty transitively enabled INFO : http initialized in ${jetty.base}/start.d/http.ini INFO : resources transitively enabled INFO : threadpool transitively enabled, ini template available with --add-modules=threadpool INFO : logging/slf4j dynamic dependency of logging-jetty INFO : bytebufferpool transitively enabled, ini template available with --add-modules=bytebufferpool INFO : mkdir ${jetty.base}/resources INFO : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties INFO : Base directory was modified 94 Jetty module, which adds the HTTP/2 protocol to the clear-text connector

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Starting Jetty yields:

$ java -jar $JETTY_HOME/start.jar

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note how Jetty is listening on port

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

66 and the protocols supported are HTTP/1.1 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

435 [i.e. clear-text HTTP/2].

With this configuration, browsers and client applications will be able to connect to port

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

66 using:

HTTP/1.1 directly [e.g. $ java -jar $JETTY_HOME/start.jar --add-module=demos 437]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

HTTP/1.1 with upgrade to HTTP/2 [e.g. $ java -jar $JETTY_HOME/start.jar --add-module=demos 438]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

HTTP/2 directly [e.g. $ java -jar $JETTY_HOME/start.jar --add-module=demos 439]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

The HTTP/2 protocol parameters can be configured by editing the properties.

When you enable support for the HTTP/3 protocol, by default the secure HTTP/2 protocol is also enabled, so that browsers or clients that do not support HTTP/3 will be able to connect to your server.

You need to enable:

the $ java -jar $JETTY_HOME/start.jar --add-modules=http 90 Jetty module, which provides the KeyStore and TLS configuration
the $ java -jar $JETTY_HOME/start.jar 04 Jetty module, which adds the HTTP/3 protocol on the HTTP/3 connector

Use the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Enabling any module Jetty module that supports secure network communication requires a valid KeyStore [read to create your own KeyStore], that, as a quick example, you can enable with the , that creates on-the-fly a KeyStore containing a self-signed certificate:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Starting Jetty yields:

$ java -jar $JETTY_HOME/start.jar

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Note how Jetty is listening on port

$ java -jar $JETTY_HOME/start.jar --add-module=demos

021 for HTTP/2 and on port

$ java -jar $JETTY_HOME/start.jar --add-module=demos

446 for HTTP/3.

The HTTP/3 protocol parameters can be configured by editing the properties.

WebSocket is a network protocol for bidirectional data communication initiated via the . WebSocket provides a simple, low-level, framing protocol layered over TCP. One or more WebSocket frames compose a WebSocket message that is either a UTF-8 text message or binary message.

Jetty provides an implementation of the following standards and specifications.

RFC-6455 - The WebSocket Protocol

Jetty supports version 13 of the released and final specification.

JSR-356 - The Java WebSocket API [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

448]

This is the official Java API for working with WebSockets.

RFC-7692 - WebSocket Per-Message Deflate Extension

This is the replacement for perframe-compression, switching the compression to being based on the entire message, not the individual frames.

RFC-8441 - Bootstrapping WebSockets with HTTP/2

Allows a single stream of an HTTP/2 connection to be upgraded to WebSocket. This allows one TCP connection to be shared by both protocols and extends HTTP/2’s more efficient use of the network to WebSockets.

Jetty provides two WebSocket implementations: one based on the Java WebSocket APIs defined by JSR 356, provided by module

$ java -jar $JETTY_HOME/start.jar --add-module=demos

449, and one based on Jetty specific WebSocket APIs, provided by module

$ java -jar $JETTY_HOME/start.jar --add-module=demos

450. The Jetty

$ java -jar $JETTY_HOME/start.jar --add-module=demos

451 module enables both implementations, but each implementation can be enabled independently.

Remember that a WebSocket connection is always initiated from the HTTP protocol [either an HTTP/1.1 upgrade or an HTTP/2 connect], therefore to enable WebSocket you need to enable HTTP.

To enable WebSocket support, you also need to decide what version of the HTTP protocol you want WebSocket to be initiated from, and whether you want secure HTTP.

For example, to enable clear-text WebSocket from HTTP/1.1, use the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

To enable secure WebSocket from HTTP/2, use the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

When enabling secure protocols you need a valid KeyStore [read to create your own KeyStore]. As a quick example, you can enable the , that creates on-the-fly a KeyStore containing a self-signed certificate:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

To enable WebSocket on both HTTP/1.1 and HTTP/2, both clear-text and secure, use the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar

Enabling the WebSocket Jetty modules comes with a startup cost because Jetty must perform two steps:

Scan web applications $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 37 files [and all the jars and classes inside it] looking for WebSocket EndPoints classes [either annotated with WebSocket API annotations or extending/implementing WebSocket API classes/interfaces]. This can be a significant cost if your web application contains a lot of classes and/or jar files.
Configure and wire WebSocket EndPoints so that WebSocket messages are delivered to the correspondent WebSocket EndPoint.

WebSocket support is by default enabled for all web applications.

For a specific web application, you can disable step 2 for Java WebSocket support [i.e. when the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

449 module is enabled] by setting the context attribute

$ java -jar $JETTY_HOME/start.jar --add-module=demos

458 to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050:

$ java -jar $JETTY_HOME/start.jar

Furthermore, for a specific web application, you can disable step 1 [and therefore also step 2] as described in the .

Web applications may need to use a WebSocket client to communicate with third party WebSocket services.

If the web application uses the Java WebSocket APIs, the WebSocket client APIs are provided by the Servlet Container and are available to the web application by enabling the WebSocket server APIs, and therefore you must enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

449 Jetty module.

However, the Java WebSocket Client APIs are quite limited [for example, they do not support secure WebSocket]. For this reason, web applications may want to use the Jetty WebSocket Client APIs.

When using the Jetty WebSocket Client APIs, web applications should include the required jars and their dependencies in the

$ java -jar $JETTY_HOME/start.jar

01 directory of the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file. Alternatively, when deploying your web applications in Jetty, you can enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

463 Jetty module to allow web applications to use the Jetty WebSocket Client APIs provided by Jetty, without the need to include jars and their dependencies in the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

37 file.

FastCGI is a network protocol primarily used by a web server to communicate to a FastCGI server.

FastCGI servers are typically used to serve web content generated by dynamic web languages, primarily PHP, but also Python, Ruby, Perl and others.

Web servers that supports FastCGI are, among others, Apache, Nginx, and Jetty. Web servers typically act as reverse proxies, converting HTTP requests that they receive from clients [browsers] to FastCGI requests that are forwarded to the FastCGI server. The FastCGI server spawns the dynamic web language interpreter, passing it the information contained in the FastCGI request and a dynamic web language script is executed, producing web content, typically HTML. The web content is then formatted into a FastCGI response that is returned to the web server, which converts it to an HTTP response that is then returned to the client.

The most well known FastCGI server is the PHP FastCGI Process Manager, or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465. In the following we will assume that

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465 is used as FastCGI server.

This is a diagram of what described above:

Jetty can be configured to act as a web server that supports FastCGI, replacing the functionality that is normally provided by Apache or Nginx. This allows users to leverage Jetty features such as the support for HTTP/1.1, HTTP/2 and HTTP/3, Jetty’s scalability, and of course Jetty’s native support for Java Web Standards such as Servlets, JSPs, etc.

With such configuration, users can not only deploy their Java Web Applications in Jetty, but also serve their WordPress site or blog or their Drupal site without having to install and manage multiple web servers.

This section explains how to configure Jetty to serve your WordPress site.

The prerequisites are:

Have $ java -jar $JETTY_HOME/start.jar --add-module=demos 465 installed on your server host, and configured to listen either on a Unix-Domain socket [such as $ java -jar $JETTY_HOME/start.jar --add-module=demos 468], or on a TCP socket [such as $ java -jar $JETTY_HOME/start.jar --add-module=demos 469].
Have WordPress installed on your server host, for example under $ java -jar $JETTY_HOME/start.jar --add-module=demos 470. For more information about how to install WordPress and the necessary PHP modules, please refer to the WordPress Installation Guide.

Then, the and/or the Jetty modules should be enabled to allow browsers to connect to Jetty.

Lastly, enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

471 module to provide FastCGI support [to convert HTTP requests from browsers to FastCGI for

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465 and vice versa], and the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

48 module to deploy your WordPress web application as a .

For example:

$ java -jar $JETTY_HOME/start.jar

The

$ java -jar $JETTY_HOME/start.jar

22 Jetty module requires a KeyStore. If you do not already have one configured, you can add the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

035 Jetty module to the command line above to create a KeyStore on-the-fly.

Now you can deploy a Jetty context XML file that represents your WordPress web application.

Use the following file as example, copy it as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

476 and customize it as necessary:

$ java -jar $JETTY_HOME/start.jar

1 Specify the WordPress installation path. 2 Specify the context path of your web application. 3 The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

477 forwards requests whose URI path matches

$ java -jar $JETTY_HOME/start.jar --add-module=demos

478 to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465. 4 The client URI regex pattern to match. 5 The URI used to forward the request to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465, where

$ java -jar $JETTY_HOME/start.jar --add-module=demos

481 is the 3rd matching group of the client URI regex pattern [int this example, the client URI path]. If

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465 is configured to listen on a TCP socket, the host and port must match the listening TCP socket. If

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465 is configured to listen on a Unix-Domain socket, the host and port values are ignored but must be present. 6 If

$ java -jar $JETTY_HOME/start.jar --add-module=demos

465 is configured to listen on a Unix-Domain socket, specify the Unix-Domain socket path, otherwise omit this line. 7 The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

077 serves static files from WordPress, such as

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

94,

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

95 and image files.

Now you can start Jetty and navigate to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

41 with your browser to enjoy WordPress:

$ java -jar $JETTY_HOME/start.jar

Secure protocols are normal protocols such as HTTP/1.1, HTTP/2 or WebSocket that are wrapped by the TLS protocol. Any network protocol based on TCP can be wrapped with TLS.

QUIC, the protocol based on UDP that transports HTTP/3, uses TLS messages but not the TLS protocol framing.

The

$ java -jar $JETTY_HOME/start.jar

22 scheme used in URIs really means

$ java -jar $JETTY_HOME/start.jar --add-module=demos

490 [or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

491, or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

and similarly the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

493 scheme used in URIs really means

$ java -jar $JETTY_HOME/start.jar --add-module=demos

494, etc. Senders wrap the underlying protocol bytes [e.g. HTTP bytes or WebSocket bytes] with the TLS protocol, while receivers first interpret the TLS protocol to obtain the underlying protocol bytes, and then interpret the wrapped bytes.

The allows you to configure a secure network connector; if other modules require encryption, they declare a dependency on the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 module.

It is the job of other Jetty modules to configure the wrapped protocol. For example, it is the that configures the wrapped protocol to be HTTP/1.1. Similarly, it is the that configures the wrapped protocol to be HTTP/2. If you enable both the

$ java -jar $JETTY_HOME/start.jar

22 and the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

18 module, you will have a single secure connector that will be able to interpret both HTTP/1.1 and HTTP/2.

Recall from the , that only modules that are explicitly enabled get their module configuration file [

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

saved in

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

38, and you want

$ java -jar $JETTY_HOME/start.jar --add-module=demos

503 to be present so that you can configure the connector properties, the KeyStore properties and the TLS properties.

Secure protocols have a slightly more complicated configuration since they require to configure a KeyStore. Refer to the for more information about how to create and manage a KeyStore.

For simple cases, you only need to configure the KeyStore path and KeyStore password as explained in .

For more advanced configuration you may want to configure the TLS protocol versions, or the ciphers to include/exclude, etc. The correct way of doing this is to create a custom and reference it in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

503:

ssl.ini

$ java -jar $JETTY_HOME/start.jar

1 Configures the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

029 property with the KeyStore password. 2 References your newly created

$ java -jar $JETTY_HOME/start.jar --add-module=demos

506.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

410 file above only shows the lines that are not commented out [you can leave the lines that are commented unmodified for future reference].

You want to create the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

506 with the following template content:

tls-config.xml

$ java -jar $JETTY_HOME/start.jar

1 Here goes your advanced configuration.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

509 file references the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

510 component [created by the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 Jetty module] that configures the KeyStore and TLS parameters, so that you can now call its APIs via XML, and you will have full flexibility for any advanced configuration you want [see below for few examples].

Use module properties whenever possible, and only resort to use a Jetty XML file for advanced configuration that you cannot do using module properties.

By default, the SSL protocols [SSL, SSLv2, SSLv3, etc.] are already excluded because they are vulnerable. To explicitly add the exclusion of TLSv1.0 and TLSv1.1 [that are also vulnerable — which leaves only TLSv1.2 and TLSv1.3 available], you want to use this XML:

tls-config.xml

$ java -jar $JETTY_HOME/start.jar

You can precisely set the list of excluded ciphers, completely overriding Jetty’s default, with this XML:

tls-config.xml

$ java -jar $JETTY_HOME/start.jar

Note how each array item specifies a regular expression that matches multiple ciphers, or specifies a precise cipher to exclude.

You can choose to create multiple XML files, and reference them all from

$ java -jar $JETTY_HOME/start.jar --add-module=demos

503, or put all your custom configurations in a single XML file.

When you create a certificate, you must specify for how many days it is valid.

The typical validity is 90 days, and while this period may seem short, it has two advantages:

Reduces the risk in case of compromised/stolen keys.
Encourages automation, i.e. certificate renewal performed by automated tools [rather than manually] at scheduled times.

To renew a certificate, you must go through the you followed to create the certificate the first time, and then you can without the need to stop Jetty.

Jetty can be configured to monitor the directory of the KeyStore file, and reload the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

87 component if the KeyStore file changed.

This feature can be enabled by activating the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

032 Jetty module:

$ java -jar $JETTY_HOME/start.jar

For more information about the configuration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

032 Jetty module, see .

If not explicitly configured, the TLS implementation is provided by the JDK you are using at runtime.

OpenJDK’s vendors may replace the default TLS provider with their own, but you can also explicitly configure an alternative TLS provider.

The standard TLS provider from OpenJDK is implemented in Java [no native code], and its performance is not optimal, both in CPU usage and memory usage.

A faster alternative, implemented natively, is Google’s Conscrypt, which is built on BoringSSL, which is Google’s fork of OpenSSL.

As Conscrypt eventually binds to a native library, there is a higher risk that a bug in Conscrypt or in the native library causes a JVM crash, while the Java implementation will not cause a JVM crash.

To use Conscrypt as the TLS provider just enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

516 Jetty module:

$ java -jar $JETTY_HOME/start.jar

Server Name Indication [SNI] is a TLS extension that clients send to indicate what domain they want to connect to during the initial TLS handshake.

Modern TLS clients [e.g. browsers] always send the SNI extension; however, older TLS clients may not send the SNI extension.

Being able to handle the SNI is important when you have and a KeyStore with multiple certificates, one for each domain.

For example, you may have deployed over a secure connector two web applications, both at context path

$ java -jar $JETTY_HOME/start.jar --add-modules=http

42, one at virtual host

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518 and one at virtual host

$ java -jar $JETTY_HOME/start.jar --add-module=demos

519. The KeyStore contains two certificates, one for

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518 and one for

$ java -jar $JETTY_HOME/start.jar --add-module=demos

519.

There are three

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 module properties that control the SNI behavior on the server: one that works at the TLS level, and two that works at the HTTP level.

The property that works at the TLS level is:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

523

Whether SNI is required at the TLS level, defaults to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. Its behavior is explained by the following table:

Table 2. Behavior of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

523 property

$ java -jar $JETTY_HOME/start.jar --add-module=demos

526

$ java -jar $JETTY_HOME/start.jar --add-module=demos

527

SNI =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

528

client receives default certificate

client receives TLS failure

SNI =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

529

client receives default certificate

client receives TLS failure

SNI =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518

client receives

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518 certificate

client receives

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518 certificate

The default certificate is the certificate returned by the TLS implementation in case there is no SNI match, and you should not rely on this certificate to be the same across Java vendors and versions, or Jetty versions, or TLS provider vendors and versions.

In the example above it could be either the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518 certificate or the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

519 certificate.

When

$ java -jar $JETTY_HOME/start.jar --add-module=demos

535, clients that don’t send a valid SNI receive a TLS failure, and their attempt to connect to the server fails. The details of this failure may not be reported and could be difficult to figure out that the failure is related to an invalid SNI.

For this reason, other two properties are defined at the HTTP level, so that clients can received an HTTP 400 response with more details about what went wrong while trying to connect to the server:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

536

Whether SNI is required at the HTTP level, defaults to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. Its behavior is similar to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

523 property above, and is explained by the following table:

Table 3. Behavior of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

536 property

$ java -jar $JETTY_HOME/start.jar --add-module=demos

526

$ java -jar $JETTY_HOME/start.jar --add-module=demos

527

SNI =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

528

Reject: 400 Bad Request

SNI =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

529

Reject: 400 Bad Request

SNI =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518

When

$ java -jar $JETTY_HOME/start.jar --add-module=demos

545, the SNI is matched against the certificate sent to the client, and only if there is a match the request is accepted.

When the request is accepted, there could be an additional check controlled by the following property:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

546

Whether the certificate sent to the client matches the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

547 header, defaults to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298. Its behavior is explained by the following table:

Table 4. Behavior of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

546 property

$ java -jar $JETTY_HOME/start.jar --add-module=demos

550

$ java -jar $JETTY_HOME/start.jar --add-module=demos

551

certificate =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518

$ java -jar $JETTY_HOME/start.jar --add-module=demos

553

Reject: 400 Bad Request

certificate =

$ java -jar $JETTY_HOME/start.jar --add-module=demos

518

$ java -jar $JETTY_HOME/start.jar --add-module=demos

555

In the normal case with the default server configuration, for a TLS clients that sends SNI, and then sends an HTTP request with the correct

$ java -jar $JETTY_HOME/start.jar --add-module=demos

547 header, Jetty will pick the correct certificate from the KeyStore based on the SNI received from the client, and accept the request.

Accepting the request does not mean that the request is responded with an HTTP 200 OK, but just that the request passed successfully the SNI checks and will be processed by the server. If the request URI is for a resource that does not exist, the response will likely be a 404 Not Found.

You may modify the default values of the SNI properties if you want stricter control over old/broken TLS clients or bad HTTP requests.

You may need to configure one or more Jetty instances behind an intermediary, typically a load balancer such as HAProxy, or a reverse proxy such as Apache HTTP Server or Nginx.

HAProxy can communicate either HTTP/1.1 or HTTP/2 to backend servers such as Jetty.

Apache HTTP Server and Nginx can only speak HTTP/1.1 to backend servers such as Jetty, and have no plans to support HTTP/2 towards backend servers.

In these setups, typically the proxy performs TLS offloading, and the communication with backend servers happens in clear-text. It is possible, however, to configure the proxy so that all the bytes arriving from the client are tunnelled opaquely to the backend Jetty server [that therefore needs to perform the TLS offloading] and vice versa the bytes arriving from the Jetty server are tunnelled opaquely to the client.

Also in these setups, the TCP/IP connection terminating on the Jetty servers does not originate from the client, but from the proxy, so that the remote IP address and port number may be reported incorrectly in backend server logs, or worse applications may not work because they need to be able to differentiate different clients based on the client IP address.

For this reason, intermediaries typically implement at least one of several de facto standards to communicate information about the original client connection to the backend Jetty server.

Jetty supports two methods to process client information sent by intermediaries:

The $ java -jar $JETTY_HOME/start.jar 08 HTTP header, defined in RFC 7239 and replacing the old $ java -jar $JETTY_HOME/start.jar 09 headers, defined in .
The Proxy Protocol, defined in .

In both methods, web applications that call

$ java -jar $JETTY_HOME/start.jar --add-module=demos

559 will receive the remote client IP address as specified by the client information sent by the intermediary, not the physical IP address of TCP connection with the intermediary. Likewise,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

560 will return the remote client IP port as specified by the client information sent by the intermediary, and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

561 will return whether the client made a secure request using the

$ java -jar $JETTY_HOME/start.jar

22 scheme as specified by the client information sent by the intermediary.

The

$ java -jar $JETTY_HOME/start.jar

08 HTTP header is added by the intermediary with information about the client and the client request, for example:

$ java -jar $JETTY_HOME/start.jar

In the example above, the intermediary added the

$ java -jar $JETTY_HOME/start.jar

08 header specifying that the client remote address is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

565 and that the request was made with the

$ java -jar $JETTY_HOME/start.jar

22 scheme.

Let’s assume you have already configured Jetty with the HTTP/1.1 protocol with the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

Support for the

$ java -jar $JETTY_HOME/start.jar

08 HTTP header [and its predecessor

$ java -jar $JETTY_HOME/start.jar

09 headers] is enabled with the

$ java -jar $JETTY_HOME/start.jar

06 Jetty module:

$ java -jar $JETTY_HOME/start.jar

With the

$ java -jar $JETTY_HOME/start.jar

06 Jetty module enabled, Jetty interprets the

$ java -jar $JETTY_HOME/start.jar

08 header and makes its information available to web applications via the standard Servlet APIs.

For further information about configuring the

$ java -jar $JETTY_HOME/start.jar

06 Jetty module, see .

The Proxy Protocol is the de facto standard, introduced by HAProxy, to communicate client information to backend servers via the TCP connection, rather than via HTTP headers.

The information about the client connection is sent as a small data frame on each newly established connection. This mechanism is therefore independent of any protocol, so it can be used for TLS, HTTP/1.1, HTTP/2, etc.

There are 2 versions of the proxy protocol: v1 and v2, both supported by Jetty.

Proxy protocol v1 is human readable, but it only carries information about the client TCP connection [IP address and IP port].

Proxy protocol v2 has a binary format, carries the information about the client TCP connection, and can carry additional arbitrary information encoded in pairs

$ java -jar $JETTY_HOME/start.jar --add-module=demos

574 where

$ java -jar $JETTY_HOME/start.jar --add-module=demos

575 is a single byte that indicates the value’s meaning, and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

576 is a variable length byte array that can encode user-defined data.

Support for the proxy protocol can be enabled for the clear-text connector or for the secure connector [or both].

Let’s assume you have already configured Jetty with the HTTP/1.1 clear-text protocol with the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar --add-modules=http

To enable proxy protocol support for the clear-text connector, enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

578 Jetty module:

$ java -jar $JETTY_HOME/start.jar

Starting Jetty yields:

$ java -jar $JETTY_HOME/start.jar

Note how in the example above the list of protocols for the clear-text connector is first

$ java -jar $JETTY_HOME/start.jar --add-module=demos

579 and then

$ java -jar $JETTY_HOME/start.jar --add-module=demos

429. For every new TCP connection, Jetty first interprets the proxy protocol bytes with the client information; after this initial proxy protocol processing, Jetty interprets the incoming bytes as HTTP/1.1 bytes.

Enabling proxy protocol support for the secure connector is similar.

Let’s assume you have already configured Jetty with the HTTP/1.1 secure protocol and the test KeyStore with the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar

Enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

582 Jetty module with the following command [issued from within the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory]:

$ java -jar $JETTY_HOME/start.jar

Starting Jetty yields:

$ java -jar $JETTY_HOME/start.jar

Note how in the example above the list of protocols for the secure connector is first

$ java -jar $JETTY_HOME/start.jar --add-module=demos

579, then

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 and then

$ java -jar $JETTY_HOME/start.jar --add-module=demos

429.

HAProxy is an open source solution that offers load balancing and proxying for TCP and HTTP based application, and can be used as a replacement for Apache or Nginx when these are used as reverse proxies.

The deployment proposed here has HAProxy playing the role that Apache and Nginx usually do: to perform the TLS offloading [that is, decrypt incoming bytes and encrypt outgoing bytes] and then forwarding the now clear-text traffic to a backend Jetty server, speaking either HTTP/1.1 or HTTP/2. Since HAProxy’s TLS offloading is based on OpenSSL, it is much more efficient than the Java implementation shipped with OpenJDK.

After you have installed HAProxy on your system, you want to configure it so that it can perform TLS offloading.

HAProxy will need a single file containing the X509 certificates and the private key, all in PEM format, with the following order:

The site certificate; this certificate’s Common Name refers to the site domain [for example: CN=*.webtide.com] and is signed by Certificate Authority
1.
The Certificate Authority
1 certificate; this certificate may be signed by Certificate Authority

2.
The Certificate Authority
2 certificate; this certificate may be signed by Certificate Authority

3; and so on until the Root Certificate Authority.
The Root Certificate Authority certificate.
The private key corresponding to the site certificate.

Refer to the for more information about generating the required certificates and private key.

Now you can create the HAProxy configuration file [in Linux it’s typically

$ java -jar $JETTY_HOME/start.jar --add-module=demos

587]. This is a minimal configuration:

haproxy.cfg

$ java -jar $JETTY_HOME/start.jar

1 The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

588 front-end accepts connections on port 80 and redirects them to use the

$ java -jar $JETTY_HOME/start.jar

22 scheme. 2 The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

590 front-end accepts connections on port 443, and it is where the TLS decryption/encryption happens. You must specify the path to the PEM file containing the TLS key material [the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

591 part], the ciphers that are suitable for HTTP/2 [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

592], and the ALPN protocols supported [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

593]. This front-end then forwards the now decrypted bytes to the backend in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

594. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

594 says that HAProxy will not try to interpret the bytes but instead opaquely forwards them to the backend. 3 The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

596 backend will forward [again in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

the clear-text bytes to a Jetty connector that talks clear-text HTTP/2 and HTTP/1.1 on port 8282. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

598 directive sends the proxy protocol v2 bytes to the backend server.

On the Jetty side, you need to enable the following modules:

$ java -jar $JETTY_HOME/start.jar

You need to specify the host [

$ java -jar $JETTY_HOME/start.jar --list-modules=*

and port [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

you have configured in HAProxy when you start Jetty:

$ java -jar $JETTY_HOME/start.jar

You want the Jetty connector that listens on port

$ java -jar $JETTY_HOME/start.jar --add-module=demos

600 to be available only to HAProxy, and not to remote clients.

For this reason, you want to specify the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

602 property on the command line [or in

$ java -jar $JETTY_HOME/start.jar

95 to make this setting persistent] to bind the Jetty connector only on the loopback interface [

$ java -jar $JETTY_HOME/start.jar --list-modules=*

45], making it available to HAProxy but not to remote clients.

If your Jetty instance runs on a different machine and/or on a different [sub]network, you may want to adjust both the back-end section of the HAProxy configuration file and the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

602 property to match accordingly.

With this configuration for HAProxy and Jetty, browsers supporting HTTP/2 will connect to HAProxy, which will decrypt the traffic and send it to Jetty. Likewise, HTTP/1.1 clients will connect to HAProxy, which will decrypt the traffic and send it to Jetty.

The Jetty connector, configured with the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

94 and the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

61 modules is able to distinguish whether the incoming bytes are HTTP/2 or HTTP/1.1 and will handle the request accordingly.

The response is relayed back to HAProxy, which will encrypt it and send it back to the remote client.

This configuration offers you efficient TLS offloading, HTTP/2 support and transparent fallback to HTTP/1.1 for clients that don’t support HTTP/1.1.

A KeyStore is a file on the file system that contains a private key and a public certificate, along with the certificate chain of the certificate authorities that issued the certificate. The private key, the public certificate and the certificate chain, but more generally the items present in a KeyStore, are typically referred to as "cryptographic material".

Keystores may encode the cryptographic material with different encodings, the most common being PKCS12, and are typically protected by a password.

Refer to the for more information about how to configure a secure connector using a KeyStore.

KeyStores are created with the JDK tool

$ java -jar $JETTY_HOME/start.jar --add-module=demos

608.

The following command creates a KeyStore file containing a private key and a self-signed certificate:

$ java -jar $JETTY_HOME/start.jar

1 the command to generate a key and certificate pair 2 the alias name of the key and certificate pair 3 specifies the number of days after which the certificate expires 4 the algorithm must be RSA [the DSA algorithm does not work for web sites] 5 indicates the strength of the key 6 the KeyStore file 7 the KeyStore type, stick with the standard PKCS12 8 the distinguished name [more below] — customize it with your values for CN, OU, O, L, S and C 9 the extension with the subject alternative names [more below] 10 verbose output

The command prompts for the KeyStore password that you must choose to protect the access to the KeyStore.

The important parts of the command above are the Common Name [CN] part of the distinguished name, and the subject alternative names [SAN].

The CN value must be the main domain you own and that you want to use for your web applications. For example, if you have bought domains

$ java -jar $JETTY_HOME/start.jar --add-module=demos

609 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

610, you want to specify

$ java -jar $JETTY_HOME/start.jar --add-module=demos

611 as your main domain.

Furthermore, to specify additional domains or subdomains within the same certificate, you must specify the SAN extension. In the example above,

$ java -jar $JETTY_HOME/start.jar --add-module=demos

612 specifies

$ java -jar $JETTY_HOME/start.jar --add-module=demos

613 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

610 as alternative names for your web applications [that you can configure using ].

In rare cases, you may want to specify IP addresses, rather than domains, in the SAN extension. The syntax in such case is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

615, which specifies as subject alternative names IPv4

$ java -jar $JETTY_HOME/start.jar --list-modules=*

45 and IPv6

$ java -jar $JETTY_HOME/start.jar --add-module=demos

617.

A single KeyStore may contain multiple key/certificate pairs. This is useful when you need to support multiple domains on the same Jetty server [typically accomplished using ].

You can create multiple key/certificate pairs as detailed in the , provided that you assign each one to a different alias.

Compliant TLS clients will send the when creating new connections, and Jetty will automatically choose the right certificate by matching the SNI name sent by the client with the CN or SAN of certificates present in the KeyStore.

Self-signed certificates are not trusted by browsers and generic clients: you need to establish a trust chain by having your self-signed certificate signed by a certificate authority [CA].

Browsers and generic clients [e.g. Java clients] have an internal list of trusted certificate authorities root certificates; they use these trusted certificates to verify the certificate they received from the server when they connect to your web applications.

To have your self-signed certificate signed by a certificate authority you first need to produce a certificate signing request [CSR]:

$ java -jar $JETTY_HOME/start.jar

1 the command to generate a certificate signing request 2 the file to save the CSR 3 the keystore that contains the self-signed certificate

Then, you have to send the CSR file to the certificate authority of your choice, and wait for their reply [they will probably require a proof that you really own the domains indicated in your certificate].

Eventually, the certificate authority will reply to you with one or more files containing the CA certificate chain, and your certificate signed by their certificate chain.

The file you receive from the CA is typically in PEM format, and you must import it back into the same KeyStore file you used to generate the CSR. You must import both the certificate chain and your signed certificate.

First, import the certificate chain:

$ java -jar $JETTY_HOME/start.jar

1 the command to import certificates 2 use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

618 alias to differentiate from the alias of the server certificate 3 the file containing the certificate chain received from the CA 4 your KeyStore file 5 specify that you trust CA certificates 6 verbose output

Then, import the signed certificate:

$ java -jar $JETTY_HOME/start.jar

Now you have a trusted certificate in your KeyStore that you can use for the domains of your web applications.

Refer to the section about configuring to configure the secure connector with your newly created KeyStore.

For the majority of secure web sites, it is the client [typically the browser] that validates the certificate sent by the server [by verifying the certificate chain]. This is the server domain certificate.

However, the TLS protocol supports a mutual authentication mode where also the client must send a certificate to the server, that the server validates.

You typically want to sign the client certificate[s] with a server certificate that you control, and you must distribute the client certificate[s] to all the clients that need it, and redistribute the client certificates when they expire. The server authentication certificate may be different from the server domain certificate, but it’s typically stored in the same KeyStore for simplicity [although under a different alias].

First, you want to create the private key and server authentication certificate that you will use to sign client certificates:

$ java -jar $JETTY_HOME/start.jar

1 use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

619 alias to differentiate from the alias of the server certificate 2 the KeyStore file 3 the CN is not that important, since this certificate will not be validated by clients 4 the extension with the basic constraints [more below]

The important difference with the is the basic constraints extension [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

that indicates that this certificates acts as a certificate authority [

$ java -jar $JETTY_HOME/start.jar --add-module=demos

621].

Now you want to export both the private key and server authentication certificate. Unfortunately, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

622 program cannot export private keys, so you need to use a different command line program like

$ java -jar $JETTY_HOME/start.jar --add-module=demos

623, or a graphical program like KeyStore Explorer.

Let’s use

$ java -jar $JETTY_HOME/start.jar --add-module=demos

623 to export the server authentication private key:

$ java -jar $JETTY_HOME/start.jar

Now let’s export the server authentication certificate:

$ java -jar $JETTY_HOME/start.jar

At this point, you want to create a client KeyStore, so that you can sign the client certificate with the server authentication cryptographic material:

$ java -jar $JETTY_HOME/start.jar

1 the client KeyStore file 2 the CN is not that important, since it will not be validated by the server

Now produce a certificate signing request [CSR]:

$ java -jar $JETTY_HOME/start.jar

Now you need to sign the CSR, but again the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

622 program does not have this functionality, and you must resort again to use

$ java -jar $JETTY_HOME/start.jar --add-module=demos

623:

$ java -jar $JETTY_HOME/start.jar

Now you need to import the server authentication certificate and the signed client certificate into the client KeyStore.

First, the server authentication certificate:

$ java -jar $JETTY_HOME/start.jar

Then, the signed client certificate:

$ java -jar $JETTY_HOME/start.jar

Now you can distribute

$ java -jar $JETTY_HOME/start.jar --add-module=demos

627 to your client[s].

Refer to the section about configuring to configure the secure connector to require client authentication.

HTTP sessions are a concept within the Servlet API which allow requests to store and retrieve information across the time a user spends in an application. Jetty offers a number of pluggable alternatives for managing and distributing/persisting sessions. Choosing the best alternative is an important consideration for every application as is the correct configuration to achieve optimum performance.

Before diving into the specifics of how to plug-in and configure various alternative HTTP session management modules, let’s review some useful terminology:

Session

is a means of retaining information across requests for a particular user. The Servlet Specification defines the semantics of sessions. Some of the most important characteristics of sessions is that they have a unique id and that their contents cannot be shared between different contexts [although the id can be]: if a session is invalidated in one context, then all other sessions that share the same id in other contexts will also be invalidated. Sessions can expire or they can be explicitly invalidated.

SessionIdManager

is responsible for allocating session ids. A Jetty server can have at most 1 SessionIdManager.

HouseKeeper

is responsible for periodically orchestrating the removal of expired sessions. This process is referred to as .

SessionHandler

is responsible for managing the lifecycle of sessions. A context can have at most 1

$ java -jar $JETTY_HOME/start.jar --add-module=demos

628.

SessionCache

is a L1 cache of in-use session objects. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629 is used by the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

628.

SessionDataStore

is responsible for all clustering/persistence operations on sessions. A

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629 uses a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 as a backing store.

CachingSessionDataStore

is an L2 cache of session data. A

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629 can use a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

634 as its backing store.

More details on these concepts can be found in the .

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632s implementations interact with other, usually third party, systems responsible for storing and/or distributing session information. Sessions can be distributed without being persisted. They can also be persisted without being distributed. Because persisting session information to a shared store is a very common way of distributing [also known as "clustering"] sessions, in the documentation we will often refer to just "persisting".

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

636 module is the base module that all other session modules depend upon. As such it will be transitively enabled if you enable any of the other session modules: you need to explicitly enable it if you wish to change any settings from their defaults.

Enabling the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

636 module puts the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

638 file onto the execution path and generates a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

639 file.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

640 file instantiates a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

641 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

642. The former is used to generate and manage session ids whilst the latter is responsible for periodic of expired sessions.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

639 file contains these configuration properties:

jetty.sessionIdManager.workerName

This uniquely identifies the jetty server instance and is applied to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

644. You can either provide a value for this property, or you can allow Jetty to try and synthesize a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

645 - the latter option is only advisable in the case of a single, non-clustered deployment. There are two ways a default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

645 can be synthesized:

if running on Google AppEngine, the $ java -jar $JETTY_HOME/start.jar --add-module=demos 645 will be formed by concatenating the values of the environment variables $ java -jar $JETTY_HOME/start.jar --add-module=demos 648 and $ java -jar $JETTY_HOME/start.jar --add-module=demos 649
otherwise, the $ java -jar $JETTY_HOME/start.jar --add-module=demos 645 will be formed by concatenating the environment variable $ java -jar $JETTY_HOME/start.jar --add-module=demos 648 and the literal $ java -jar $JETTY_HOME/start.jar 37.

So, if you’re not running on Google AppEngine, and you haven’t configured one, the workerName will always be:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

653.

If you have more than one Jetty instance, it is crucial that you configure the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

645 differently for each instance.

jetty.sessionScavengeInterval.seconds

This is the period in seconds between runs of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

642, responsible for orchestrating the removal of expired sessions. By default it will run approximately every 600 secs [ie 10 mins]. As a rule of thumb, you should ensure that the interval is shorter than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

656 of your sessions to ensure that they are promptly scavenged. On the other hand, if you have a backend store configured for your sessions, too frequently can increase the load on it.

Don’t forget that the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

656 is specified in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 in minutes and the value of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

659 is in seconds.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

642 is responsible for the periodic initiation of session scavenge cycles. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

659 property in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

639 controls the periodicity of the cycle.

The HouseKeeper semi-randomly adds an additional 10% to the configured

$ java -jar $JETTY_HOME/start.jar --add-module=demos

663. This is to prevent multiple nodes in a cluster that are all started at once from syncing up scavenge cycles and placing extra load on the configured persistence mechanism.

A session whose expiry time has been exceeded is considered eligible for scavenging. The session might be present in a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629 and/or present in the session persistence/clustering mechanism.

Scavenging occurs for all contexts on a server at every cycle. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

642 sequentially asks the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

628 in each context to find and remove expired sessions. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

628 works with the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 to evaluate candidates for expiry held in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629, and also to sweep the persistence mechanism to find expired sessions.

The sweep takes two forms: once per cycle the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 searches for sessions for its own context that have expired; infrequently, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 will widen the search to expired sessions in all contexts. The former finds sessions that are no longer in this context’s

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629, and using some heuristics, are unlikely to be in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629 of the same context on another node either. These sessions will be loaded and fully expired, meaning that

$ java -jar $JETTY_HOME/start.jar --add-module=demos

674 will be called for them. The latter finds sessions that have not been disposed of by scavenge cycles on any other context/node. As these will be sessions that expired a long time ago, and may not be appropriate to load by the context doing the scavenging, these are summarily deleted without

$ java -jar $JETTY_HOME/start.jar --add-module=demos

674 being called.

A combination of these sweeps should ensure that the persistence mechanism does not fill over time with expired sessions.

As aforementioned, the sweep period needs to be short enough to find expired sessions in a timely fashion, but not so often that it overloads the persistence mechanism.

In this section we will look at the alternatives for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629, i.e. the L1 cache of in-use session objects. Jetty ships with 2 alternatives: an in-memory cache, and a null cache. The latter does not actually do any caching of sessions, and can be useful if you either want to minimize your support for sessions, or you are in a clustered deployment without a sticky loadbalancer.

The go into more detail on this.

If you wish to change any of the default configuration values you should enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

677 . The name

$ java -jar $JETTY_HOME/start.jar --add-module=demos

678 harks back to historical Jetty session implementations, whereby sessions were kept in memory using a HashMap.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

679 contains the following configurable properties:

jetty.session.evictionPolicy

Integer, default -1. This controls whether session objects that are held in memory are subject to eviction from the cache. Eviction means that the session is removed from the cache. This can reduce the memory footprint of the cache and can be useful if you have a lot of sessions. Eviction is usually used in conjunction with a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 that persists sessions. The eviction strategies and their corresponding values are:

-1 [NO EVICTION]

sessions are never evicted from the cache. The only way they leave are via expiration or invalidation.

0 [EVICT AFTER USE]

sessions are evicted from the cache as soon as the last active request for it finishes. The session will be passed to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 to be written out before eviction.

\>= 1 [EVICT ON INACTIVITY]

any positive number is the time in seconds after which a session that is in the cache but has not experienced any activity will be evicted. Use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

682 property to force a session write before eviction.

If you are not using one of the session store modules, ie one of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

683s, then sessions will be lost when the context is stopped, or the session is evicted.

jetty.session.saveOnInactiveEvict

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. This controls whether a session will be persisted to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 if it is being evicted due to the EVICT ON INACTIVITY policy. Usually sessions will be written to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 whenever the last simultaneous request exits the session. However, as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

687 can be configured to skip some writes [see the documentation for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

688 module that you are using], this option is provided to ensure that the session will be written out.

Be careful with this option, as in clustered scenarios it would be possible to "re-animate" a session that has actually been deleted by another node.

jetty.session.saveOnCreate

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. Controls whether a session that is newly created will be immediately saved to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 or lazily saved as the last request for the session exits. This can be useful if the request dispatches to another context and needs to re-use the same session id.

jetty.session.removeUnloadableSessions

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. Controls whether the session cache should ask a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 to delete a session that cannot be restored - for example because it is corrupted.

jetty.session.flushOnResponseCommit

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. If true, if a session is "dirty" - ie its attributes have changed - it will be written to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 as the response is about to commit. This ensures that all subsequent requests whether to the same or different node will see the updated session data. If false, a dirty session will only be written to the backing store when the last simultaneous request for it leaves the session.

jetty.session.invalidateOnShutdown

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. If true, when a context is shutdown, all sessions in the cache are invalidated and deleted both from the cache and from the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632.

You may need to use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

697 module if your clustering setup does not have a sticky load balancer, or if you want absolutely minimal support for sessions. If you enable this module, but you don’t enable a module that provides session persistence [ie one of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

688 modules], then sessions will neither be retained in memory nor persisted.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

699 contains the following configurable properties:

jetty.session.saveOnCreate

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. Controls whether a session that is newly created will be immediately saved to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 or lazily saved as the last request for the session exits. This can be useful if the request dispatches to another context and needs to re-use the same session id.

jetty.session.removeUnloadableSessions

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. Controls whether the session cache should ask a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 to delete a session that cannot be restored - for example because it is corrupted.

jetty.session.flushOnResponseCommit

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. If true, if a session is "dirty" - ie its attributes have changed - it will be written to the backing store as the response is about to commit. This ensures that all subsequent requests whether to the same or different node will see the updated session data. If false, a dirty session will only be written to the backing store when the last simultaneous request for it leaves the session.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

705 Jetty module supports persistent storage of session data in a filesystem.

Persisting sessions to the local file system should never be used in a clustered environment.

Enabling this module creates the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

706 directory. By default session data will be saved to this directory, one file representing each session.

File names follow this pattern:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

707

expiry

This is the expiry time in milliseconds since the epoch.

contextpath

This is the context path with any special characters, including

$ java -jar $JETTY_HOME/start.jar --add-modules=http

42, replaced by the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

709 underscore character. For example, a context path of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

710 would become

$ java -jar $JETTY_HOME/start.jar --add-module=demos

711. A context path of simply

$ java -jar $JETTY_HOME/start.jar --add-modules=http

42 becomes just

$ java -jar $JETTY_HOME/start.jar --add-module=demos

713.

virtualhost

This is the first virtual host associated with the context and has the form of 4 digits separated by

$ java -jar $JETTY_HOME/start.jar --add-module=demos

714 characters:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

715. If there are no virtual hosts associated with a context, then

$ java -jar $JETTY_HOME/start.jar --add-module=demos

716 is used.

This is the unique id of the session.

Putting all of the above together as an example, a session with an id of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

717 for the context with path

$ java -jar $JETTY_HOME/start.jar --add-module=demos

718 with no virtual hosts and an expiry of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

719 would have a file name of:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

720

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

639 file contains the following properties which may be modified to customise filesystem session storage:

jetty.session.storeDir

The default is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

706. This is a path that defines the location for storage of session files.

jetty.session.file.deleteUnrestorableFiles

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. If set to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298, unreadable files will be deleted. This is useful to prevent repeated logging of the same error when the scavenger periodically [re-]attempts to load the corrupted information for a session in order to expire it.

jetty.session.gracePeriod.seconds

Integer, default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 will always change. For heavily-used, read-mostly sessions you can save some time by skipping some writes for sessions for which only these fields have changed [ie no session attributes changed]. The value of this property is used to skip writes for these kinds of sessions: the session will only be written out if the time since the last write exceeds the value of this property.

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

Enabling the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

735 module configures Jetty to persist session data in a relational database.

After enabling the module, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

736 file contains the following customizable properties:

jetty.session.gracePeriod.seconds

Integer, default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

db-connection-type

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

747. Set to either

$ java -jar $JETTY_HOME/start.jar --add-module=demos

747 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

749 depending on the type of connection being used. Depending which you select, there are additional properties available:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

747

jetty.session.jdbc.datasourceName

Name of the remote datasource.

$ java -jar $JETTY_HOME/start.jar --add-module=demos

749

jetty.session.jdbc.driverClass

Name of the JDBC driver that controls access to the remote database, such as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

752

jetty.session.jdbc.driverUrl

URL of the database which includes the driver type, host name and port, service name and any specific attributes unique to the database, such as a username. As an example, here is a mysql connection with the username appended:

$ java -jar $JETTY_HOME/start.jar --add-module=demos

753.

jetty.session.jdbc.blobType

Optional. Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

754 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

755 for Postgres. This is the keyword used by the particular database to identify the blob data type. If netiher default is suitable you can set this value explicitly.

jetty.session.jdbc.longType

Optional. Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

756 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

757 for Oracle. This is the keyword used by the particular database to identify the long integer data type. Set this explicitly if neither of the default values is appropriate.

jetty.session.jdbc.stringType

Optional. Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

758. This is the keyword used by the particular database to identify character type. If the default is not suitable, you can set this value explicitly.

jetty.session.jdbc.schema.schemaName jetty.session.jdbc.schema.catalogName

Optional. The exact meaning of these two properties is dependent on your database vendor, but can broadly be described as further scoping for the session table name. See //en.wikipedia.org/wiki/Database_schema and //en.wikipedia.org/wiki/Database_catalog. These extra scoping names can come into play at startup time when Jetty determines if the session table already exists, or otherwise creates it on-the-fly. If you have employed either of these concepts when you pre-created the session table, or you want to ensure that Jetty uses them when it auto-creates the session table, then you have two options: either set them explicitly, or let Jetty infer them from a database connection [obtained using either a Datasource or Driver according to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

759 you have configured]. To set them explicitly, uncomment and supply appropriate values for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

760 and/or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

761 properties. Alternatively, to allow Jetty to infer them from a database connection, use the special string

$ java -jar $JETTY_HOME/start.jar --add-module=demos

762 instead. If you leave them blank or commented out, then the sessions table will not be scoped by schema or catalog name.

jetty.session.jdbc.schema.table

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

763. This is the name of the table in which session data is stored.

jetty.session.jdbc.schema.accessTimeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

764. This is the name of the column that stores the time - in ms since the epoch - at which a session was last accessed

jetty.session.jdbc.schema.contextPathColumn

Default

$ java -jar $JETTY_HOME/start.jar

14. This is the name of the column that stores the

$ java -jar $JETTY_HOME/start.jar

14 of a session.

jetty.session.jdbc.schema.cookieTimeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

767. This is the name of the column that stores the time - in ms since the epoch - that the cookie was last set for a session.

jetty.session.jdbc.schema.createTimeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

768. This is the name of the column that stores the time - in ms since the epoch - at which a session was created.

jetty.session.jdbc.schema.expiryTimeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

769. This is name of the column that stores - in ms since the epoch - the time at which a session will expire.

jetty.session.jdbc.schema.lastAccessTimeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726. This is the name of the column that stores the time - in ms since the epoch - that a session was previously accessed.

jetty.session.jdbc.schema.lastSavedTimeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

771. This is the name of the column that stores the time - in ms since the epoch - at which a session was last written.

jetty.session.jdbc.schema.idColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

772. This is the name of the column that stores the id of a session.

jetty.session.jdbc.schema.lastNodeColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

773. This is the name of the column that stores the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

645 of the last node to write a session.

jetty.session.jdbc.schema.virtualHostColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

775. This is the name of the column that stores the first virtual host of the context of a session.

jetty.session.jdbc.schema.maxIntervalColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

776. This is the name of the column that stores the interval - in ms - during which a session can be idle before being considered expired.

jetty.session.jdbc.schema.mapColumn

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

777. This is the name of the column that stores the serialized attributes of a session.

Enabling the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

778 module configures Jetty to store session data in MongoDB.

Because MongoDB is not a technology provided by the Eclipse Foundation, you will be prompted to assent to the licenses of the external vendor [Apache in this case] during the install. Jars needed by MongoDB are downloaded and stored into a directory named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

779.

If you want to use updated versions of the jar files automatically downloaded by Jetty, you can place them in the associated

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory and use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

781 command line option to prevent errors when starting your server.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

782 file contains these configurable properties:

jetty.session.mongo.dbName

Default is "HttpSessions". This is the name of the database in MongoDB used to store the session collection.

jetty.session.mongo.collectionName

Default is "jettySessions". This is the name of the collection in MongoDB used to store all of the sessions.

The connection type-

You can connect to MongoDB either using a host/port combination, or a URI. By default, the host/port method is selected, but you can change this by commenting out the unwanted method, and uncommenting the other one.

connection-type=address

Used when utilizing a direct connection to the MongoDB server.

jetty.session.mongo.host

Host name or address for the remote MongoDB instance.

jetty.session.mongo.port

Port number for the remote MongoDB instance.

connection-type=uri

Used when utilizing MongoURI for secured connections.

jetty.session.mongo.connectionString

The string defining the MongoURI value, such as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

783. More information on how to format the MongoURI string can be found in the official documentation for mongo.

You will only use one

$ java -jar $JETTY_HOME/start.jar --add-module=demos

784 at a time, either

$ java -jar $JETTY_HOME/start.jar --add-module=demos

785 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

786. If both are utilized in your

$ java -jar $JETTY_HOME/start.jar --add-module=demos

787, only the last

$ java -jar $JETTY_HOME/start.jar --add-module=demos

784 configured in the file will be used.

jetty.session.gracePeriod.seconds

Integer, in seconds. Default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

In order to persist/cluster sessions using Infinispan, Jetty needs to know how to contact Infinispan. There are two options: a remote Infinispan instance, or an in-process Infinispan instance. The former is referred to as "remote" Infinispan and the latter as "embedded" Infinispan. If you wish Jetty to be able to expired sessions, you will also need to enable the appropriate

$ java -jar $JETTY_HOME/start.jar --add-module=demos

799 module.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

800 module configures Jetty to talk to an external Infinispan instance to store session data.

Because Infinispan is not a technology provided by the Eclipse Foundation, you will be prompted to assent to the licenses of the external vendor [Apache in this case].

Infinispan-specific jar files are download to the directory named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

801.

In addition to adding these modules to the classpath of the server it also added several ini configuration files to the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

802 directory.

If you have updated versions of the jar files automatically downloaded by Jetty, you can place them in the associated

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory and use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

781 command line option to prevent errors when starting your server.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

805 contains the following configurable properties:

jetty.session.infinispan.remoteCacheName

Default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

806. This is the name of the cache in Infinispan where sessions will be stored.

jetty.session.infinispan.idleTimeout.seconds

Integer, in seconds, default

$ java -jar $JETTY_HOME/start.jar

37. This is the amount of time, in seconds, that a session entry in Infinispan can be idle [ie neither read nor written] before Infinispan will delete its entry. Usually, you do not want to set a value for this, as you want Jetty to manage all session expiration [and call any HttpSessionListeners]. You should enable the to allow jetty to for expired sessions. If you do not, then there is the possibility that sessions can be left in Infinispan but no longer referenced by any Jetty node [so called "zombie" or "orphan" sessions], in which case you can use this feature to ensure their removal.

You should make sure that the number of seconds you specify is larger than the configured

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 for sessions.

jetty.session.gracePeriod.seconds

Integer, default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

819 module allows Jetty to expired sessions. Note that this is an additional module, to be used in conjunction with the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

800 module.

There are no configuration properties associated with this module.

Enabling the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

821 module runs an in-process instance of Infinispan.

Because Infinispan is not a technology provided by the Eclipse Foundation, you will be prompted to assent to the licenses of the external vendor [Apache in this case]. Infinispan-specific jar files will be downloaded and saved to a directory named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

801.

If you have updated versions of the jar files automatically downloaded by Jetty, you can place them in the associated

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory and use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

781 command line option to prevent errors when starting your server.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

825 contains the following configurable properties:

jetty.session.infinispan.idleTimeout.seconds

Integer, in seconds, default

$ java -jar $JETTY_HOME/start.jar

37. This is the amount of time, in seconds, that a session entry in Infinispan can be idle [ie neither read nor written] before Infinispan will delete its entry. Usually, you do not want to set a value for this, as you want Jetty to manage all session expiration [and call any HttpSessionListeners]. You should enable the to allow Jetty to for expired sessions. If you do not, then there is the possibility that expired sessions can be left in Infinispan.

You should make sure that the number of seconds you specify is larger than the configured

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 for sessions.

jetty.session.gracePeriod.seconds

Integer, default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

From Jetty-9.4.13 onwards, we have changed the format of the serialized session when using a remote cache [ie using hotrod]. Prior to release 9.4.13 we used the default Infinispan serialization, however this was not able to store sufficient information to allow Jetty to properly deserialize session attributes in all circumstances. See issue //github.com/eclipse/jetty.project/issues/2919 for more background.

We have provided a conversion program which will convert any sessions stored in Infinispan to the new format.

We recommend that you backup your stored sessions before running the conversion program.

How to use the converter:

$ java -jar $JETTY_HOME/start.jar

The classpath

Must contain the servlet-api, jetty-util, jetty-server, jetty-infinispan and infinispan-remote jars. If your sessions contain attributes that use application classes, you will also need to also put those classes onto the classpath. If your session has been authenticated, you may also need to include the jetty-security and jetty-http jars on the classpath.

Parameters

When used with no arguments the usage message is printed. When used with the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

837 parameter the conversion is performed. When used with both

$ java -jar $JETTY_HOME/start.jar --add-module=demos

837 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

839 parameters, sessions are checked for whether or not they are converted.

-Dhost

you can optionally provide a system property with the address of your remote Infinispan server. Defaults to the localhost.

-Dverbose

defaults to false. If true, prints more comprehensive stacktrace information about failures. Useful to diagnose why a session is not converted.

cache-name

the name of the remote cache containing your sessions. This is mandatory.

check

the optional check command will verify sessions have been converted. Use it after doing the conversion.

To perform the conversion, run the InfinispanSessionLegacyConverter with just the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

837, and optionally the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

841 system property. The following command will attempt to convert all sessions in the cached named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

842 on the machine

$ java -jar $JETTY_HOME/start.jar --add-module=demos

843, ensuring that application classes in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

844 directory are on the classpath:

$ java -jar $JETTY_HOME/start.jar

If the converter fails to convert a session, an error message and stacktrace will be printed and the conversion will abort. The failed session should be untouched, however it is prudent to take a backup of your cache before attempting the conversion.

Hazelcast can be used to cluster session information in one of two modes: either remote or embedded. Remote mode means that Hazelcast will create a client to talk to other instances, possibly on other nodes. Embedded mode means that Hazelcast will start a local instance and communicate with that.

Enabling the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

845 module allows jetty to communicate with a remote Hazelcast instance to cluster session data.

Because Hazelcast is not a technology provided by the Eclipse Foundation, you will be prompted to assent to the licenses of the external vendor [Apache in this case].

Hazelcast-specific jar files will be downloaded and saved to a directory named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

846.

If you have updated versions of the jar files automatically downloaded by Jetty, you can place them in the associated

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory and use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

781 command line option to prevent errors when starting your server.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

849 contains a list of all the configurable options for the Hazelcast module:

jetty.session.hazelcast.mapName

The default is "jetty-distributed-session-map". This is the name of the Map in Hazelcast where sessions will be stored.

jetty.session.hazelcast.onlyClient

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298. The Hazelcast instance will be configured in client mode.

jetty.session.hazelcast.configurationLocation

Optional. This is the path to an external Hazelcast xml configuration file.

jetty.session.hazelcast.useQueries

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050. If

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298, Jetty will use Hazelcast queries to find sessions to . If

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050 sessions that are not currently in a cannot be , and will need to be removed by some external process.

jetty.session.hazelcast.addresses

Optional. These are the addresses of remote Hazelcast instances with which to communicate.

jetty.session.gracePeriod.seconds

Integer, in seconds. Default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

Be aware that if your session attributes contain classes from inside your webapp [or Jetty classes] then you will need to put these classes onto the classpath of all of your Hazelcast instances.

This will run an in-process instance of Hazelcast. This can be useful for example during testing. To enable this you enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

864 module.

Because Hazelcast is not a technology provided by the Eclipse Foundation, you will be prompted to assent to the licenses of the external vendor [Apache in this case].

Hazelcast-specific jar files will be downloaded to a directory named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

846.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

866 contains a list of all the configurable options for the Hazelcast module:

jetty.session.hazelcast.mapName

The default is "jetty-distributed-session-map". This is the name of the Map in Hazelcast where sessions will be stored. jetty.session.hazelcast.hazelcastInstanceName Default is "JETTY_DISTRIBUTED_SESSION_INSTANCE". This is the unique name of the Hazelcast instance that will be created.

jetty.session.hazelcast.configurationLocation

Optional. This is the path to an external Hazelcast xml configuration file.

jetty.session.hazelcast.useQueries

Boolean, default

$ java -jar $JETTY_HOME/start.jar --add-module=demos

867, Jetty will use Hazelcast queries to find expired sessions to . If

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050 sessions that are not currently in a cannot be , and will need to be removed by some external process.

jetty.session.gracePeriod.seconds

Integer, in seconds. Default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

If your session attributes contain classes from inside your webapp [or jetty classes] then you will need to put these classes onto the classpath of all of your hazelcast instances. In the case of embedded hazelcast, as it is started before your webapp, it will NOT have access to your webapp’s classes - you will need to extract these classes and put them onto the jetty server’s classpath.

Jetty can store http session information into GCloud by enabling the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

879 module.

Before running Jetty, you will need to choose one of the following methods to set up the local environment to enable remote GCloud DataStore communications.

Using the GCloud SDK:
- Ensure you have the GCloud SDK installed: //cloud.google.com/sdk/?hl=en
- Use the GCloud tool to set up the project you created in the preparation step: $ java -jar $JETTY_HOME/start.jar --add-module=demos 880
- Use the GCloud tool to authenticate a Google account associated with the project created in the preparation step: $ java -jar $JETTY_HOME/start.jar --add-module=demos 881
Using environment variables
- Define the environment variable $ java -jar $JETTY_HOME/start.jar --add-module=demos 882 with the project id you created in the preparation step.
- Generate a JSON and then define the environment variable $ java -jar $JETTY_HOME/start.jar --add-module=demos 883

Using some special, composite indexes can speed up session search operations, although it may make write operations slower. By default, indexes will not be used. In order to use them, you will need to manually upload a file that defines the indexes. This file is named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

884 and you can find it in your distribution in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

885.

Follow the instructions to upload the pre-generated

$ java -jar $JETTY_HOME/start.jar --add-module=demos

884 file.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

879 module provides GCloud support for storing session data.

Because the Google Cloud DataStore is not a technology provided by the Eclipse Foundation, when enabling the module you will be prompted to assent to the licenses of the external vendor.

As GCloud requires certain Java Commons Logging features to work correctly, Jetty routes these through SLF4J. By default, Jetty implements the SLF4J api, but you can choose a different logging implementation by following the instructions

If you want to use updated versions of the jar files automatically downloaded during the module enablement, you can place them in the associated

$ java -jar $JETTY_HOME/start.jar --add-modules=http

56 directory and use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

781 command line option to prevent errors when starting your server.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

890 file contains all of the configurable properties for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

879 module:

jetty.session.gcloud.maxRetries

Integer. Default 5. Maximum number of retries to connect to GCloud DataStore to write a session.

jetty.session.gcloud.backoffMs

Integer in milliseconds. Default 1000. Number of milliseconds between successive attempts to connect to the GCloud DataStore to write a session.

jetty.session.gracePeriod.seconds

Integer, in seconds. Default 3600. Used during session . Multiples of this period are used to define how long ago a stored session must have expired before it should be .

jetty.session.savePeriod.seconds

Integer, in seconds, default is

$ java -jar $JETTY_HOME/start.jar

37. Whenever a session is accessed by a request, its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 are updated. Even if your sessions are read-mostly, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

726 and

$ java -jar $JETTY_HOME/start.jar --add-module=demos

You should be careful in the use of this property in clustered environments: if you set too large a value for this property, the session may not be written out sufficiently often to update its

$ java -jar $JETTY_HOME/start.jar --add-module=demos

727 time thus making it appear to other nodes that it has expired. Thorough consideration of the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731 of the session when setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 is imperative - it would be undesirable to set a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

732 that is larger than the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

731.

jetty.session.gcloud.namespace

Optional. Sets the namespace for GCloud Datastore to use. If set, partitions the visibility of session data between webapps, which is helpful for multi-tenant deployments. More information can be found here.

Configuration of the stored session object and its fields names-

You should very rarely, if ever, need to change these defaults.

jetty.session.gcloud.model.kind

The default is "GCloudSession". This is the type of the object that is stored in GCloud.

jetty.session.gcloud.model.id

The default is "id". This is the session id.

jetty.session.gcloud.model.contextPath

The default is "contextPath". This is the canonicalized context path of the context to which the session belongs.

jetty.session.gcloud.model.vhost

The default is "vhost". This is the canonicalized virtual host of the context to which the session belongs.

jetty.session.gcloud.model.accessed

The default is "accessed". This is the current access time of the session.

jetty.session.gcloud.model.lastAccessed

The default is "lastAccessed". This is the last access time of the session.

jetty.session.gcloud.model.createTime

The default is "createTime". This is the time, in ms since the epoch, at which the session was created.

jetty.session.gcloud.model.cookieSetTime

The default is "cookieSetTime". This is the time at which the session cookie was last set.

jetty.session.gcloud.model.lastNode

The default is "lastNode". This is the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

645 of the last node to manage the session.

jetty.session.gcloud.model.expiry

The default is "expiry". This is the time, in ms since the epoch, at which the session will expire.

jetty.session.gcloud.model.maxInactive

The default is "maxInactive". This is the session timeout in ms.

jetty.session.gcloud.model.attributes

The default is "attributes". This is a map of all the session attributes.

If your chosen persistence technology is slow, it can be helpful to locally cache the session data. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

634 is a special type of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 that locally caches session data, which makes reads faster. It writes-through to your chosen type of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 when session data changes.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

906 uses

$ java -jar $JETTY_HOME/start.jar --add-module=demos

907 to perform caching of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

908.

To enable it with the Jetty distribution, enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

909 module, along with your chosen

$ java -jar $JETTY_HOME/start.jar --add-module=demos

683 module.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

911 contains the following configurable properties:

jetty.session.memcached.host

Default value is

$ java -jar $JETTY_HOME/start.jar

25. This is the host on which the memcached server resides.

jetty.session.memcached.port

Default value is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

913. This is the port on which the memcached server is listening.

jetty.session.memcached.expirySec

Default value

$ java -jar $JETTY_HOME/start.jar

37. This is the length of time in seconds that an item can remain in the memcached cache, where 0 indicates indefinitely.

jetty.session.memcached.heartbeats

Default value

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298. Whether the memcached system should generate heartbeats.

Preferably, your cluster will utilize a sticky load balancer. This will route requests for the same session to the same Jetty instance. In this case, the can be used to keep in-use session objects . You can fine-tune the cache by controlling how long session objects remain in memory with the .

If you have a large number of sessions or very large session objects, then you may want to manage your memory allocation by controlling the amount of time session objects spend in the cache. The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

917 eviction policy will remove a session object from the cache as soon as the last simultaneous request referencing it exits. Alternatively, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

918 policy will remove a session object from the cache after a configurable amount of time has passed without a request referencing it.

If your sessions are very long lived and infrequently referenced, you might use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

919 to control the size of the cache.

If your sessions are small, or relatively few or stable in number or they are read-mostly, then you might select the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

920 policy. With this policy, session objects will remain in the cache until they either expire or are explicitly invalidated.

If you have a high likelihood of simultaneous requests for the same session object, then the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

917 policy will ensure the session object stays in the cache as long as it is needed.

Without a sticky load balancer requests for the same session may arrive on any node in the cluster. This means it is likely that the copy of the session object in any

$ java -jar $JETTY_HOME/start.jar --add-module=demos

629 is likely to be out-of-date, as the session was probably last accessed on a different node. In this case, your choices are to use either the or to de-tune the . If you use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

923 all session object caching is avoided. This means that every time a request references a session it must be read in from persistent storage. It also means that there can be no sharing of session objects for multiple requests for the same session: each will have their own independent session object. Furthermore, the outcome of session writes are indeterminate because the Servlet Specification does not mandate ACID transactions for sessions.

If you use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

916, there is a risk that the caches on some nodes will contain out-of-date session information as simultaneous requests for the same session are scattered over the cluster. To mitigate this somewhat you can use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

917 eviction policy: this will ensure that the session is removed from the cache as soon as the last simultaneous request for it exits. Again, due to the lack of session transactionality, the ordering outcome of write operations cannot be guaranteed. As the session is cached while at least one request is accessing it, it is possible for multiple simultaneous requests to share the same session object.

For various reasons it might not be possible for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

632 to re-read a stored session. One scenario is that the session stores a serialized object in its attributes, and after a re-deployment there in an incompatible class change. Setting the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

679 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

699 property

$ java -jar $JETTY_HOME/start.jar --add-module=demos

931 to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298 will allow the unreadable session to be removed from persistent storage. This can be useful for preventing the from continually generating errors on the same expired, but un-readable session.

The auto discovery features of the Servlet Specification can make deployments slow and uncertain. Auto discovery of web application configuration can be useful during the development as it allows new features and frameworks to be enabled simply by dropping in a jar file. However for production deployment, the need to scan the contents of many jars can have a significant impact at startup time.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

933 module allows a webapp to be pre-scanned, making startup predictable and faster. During scanning all declarative configuration [ie from web.xml, web-fragment.xml and annotations] are encoded into an effective

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191, called

$ java -jar $JETTY_HOME/start.jar --add-module=demos

935, which can be inspected to understand what will be deployed.

Programmatic configuration is not encoded into the generated

$ java -jar $JETTY_HOME/start.jar --add-module=demos

936 file.

With

$ java -jar $JETTY_HOME/start.jar --add-module=demos

933, webapps that took many seconds to scan and deploy can now be deployed in a few hundred milliseconds.

Enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

933 module for your jetty base:

$ java -jar $JETTY_HOME/start.jar

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

939 file contains these configurable parameters:

jetty.quickstart.mode

The values are:

AUTO

Allows jetty to run either with or without a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

936 file. If jetty detects the file, then it will be used, otherwise the app is started normally.

GENERATE

In this mode, jetty will generate a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

936 file and then terminate. Use this mode first before changing to either

$ java -jar $JETTY_HOME/start.jar --add-module=demos

942 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

943.

QUICKSTART

In this mode, if jetty does not detect a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

936 file then jetty will not start.

jetty.quickstart.origin

Use this parameter to set the name of the attribute in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

936 file that contains the origin of each element. Knowing the descriptor or annotation from which each element derives can be useful for debugging. Note that the origin attribute does not conform to the web xml schema, so if you deploy with xml validation, you’ll see errors. It is probably best to do a few trial runs with the attribute set, then turn it off for final generation.

jetty.quickstart.xml

Use this parameter to change the name of the generated file. By default this is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

936 in the webapp’s

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

98 directory. The file named by this parameter will always be interpreted relative to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

98.

If your webapp is a war file, you will need to either first unpack it yourself, or use a context xml file [or code equivalent] that calls

$ java -jar $JETTY_HOME/start.jar --add-module=demos

949. If you allow Jetty to do the unpacking, it will use the usual mechanisms to find the location to which to unpack. Note that by default Jetty unpacks to a temporary location which is not reused between executions. So either specify the directory to which to unpack, or make a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

950 directory in your base to ensure the unpacked war is preserved and reused across restarts.

Enable the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

951 module if your webapp - or any of its third party libraries - uses any of the following:

Annotations:
- @Resource
- @Resources
- @PostConstruct
- @PreDestroy
- @DeclaredRoles
- @RunAs
- @MultipartConfig
- @WebServlet
- @WebFilter
- @WebListener
- @WebInitParam
- @ServletSecurity, @HttpConstraint, @HttpMethodConstraint
- @HandlesTypes
javax.servlet.ServletContainerInitializers or jakarta.servlet.ServletContainerInitializers
JSP

According to more recent versions of the Jakarta Servlet Specification, the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 file can contain the attribute

$ java -jar $JETTY_HOME/start.jar --add-module=demos

953. If this is set to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298, then no annotation scanning takes place, and your descriptor must contain the equivalent xml statements of any annotations.

If it is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

955, or your

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 predates the inclusion of this attribute, annotation scanning is required to take place.

To prevent annotation scanning you can use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

957 method. Here’s an example context XML file that calls this method:

$ java -jar $JETTY_HOME/start.jar

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

174, which is the Jetty component that represents a standard Servlet web application. 2 Specifies that scanning should not take place.

However, despite

$ java -jar $JETTY_HOME/start.jar --add-module=demos

959, scanning of classes may still occur because of

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960. Classes implementing this interface are found by Jetty using the javax.util.ServiceLoader mechanism, and if one is present and it includes the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

961 annotation, then Jetty must scan the class hierarchy of the web application. This may be very time-consuming if you have many jars.

Jetty can reduce the time taken by limiting the jars that are scanned.

By default, Jetty will not scan any classes that are on the container’s classpath.

Sometimes, you may have third party libraries on the container’s classpath that you need to be scanned. In this case, use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

962 context attribute to define which container jars and class directories to scan. The value of this attribute is a regular expression.

Here’s an example from a context XML file that includes any jar whose name starts with

$ java -jar $JETTY_HOME/start.jar --add-module=demos

963 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

964, or a directory named

$ java -jar $JETTY_HOME/start.jar --add-module=demos

965:

$ java -jar $JETTY_HOME/start.jar

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

174, which is the Jetty component that represents a standard Servlet web application. 2 Specifies a context attribute. 3 Specifies the name of the context attribute. 4 Specifies the value of the context attribute.

Note that the order of the patterns defines the ordering of the scanning of the jars or class directories.

By default, Jetty will scan all classes from

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

99 and all jars from

$ java -jar $JETTY_HOME/start.jar

01 according to the order, if any, established by absolute or relative ordering clauses in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191.

If your webapp contains many jar files that you know do not contain any annotations, you can significantly speed up deployment by omitting them from scanning. However, be careful if your webapp uses a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 with a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

961 annotation that you don’t exclude jars that contain classes matching the annotation.

Use the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

972 context attribute to define a regular expression for jars and class directories to select for scanning.

Here’s an example of a context XML file that sets a pattern that matches any jar on the webapp’s classpath that starts with

$ java -jar $JETTY_HOME/start.jar --add-module=demos

973:

$ java -jar $JETTY_HOME/start.jar

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

By default, Jetty performs annotation scanning in a multi-threaded manner in order to complete it in the minimum amount of time.

If you don’t want multi-threaded scanning, you can configure Jetty to revert to single-threaded scanning. There are several options to configure this:

Set the context attribute $ java -jar $JETTY_HOME/start.jar --add-module=demos 975 to $ java -jar $JETTY_HOME/start.jar --add-module=demos 050
Set the $ java -jar $JETTY_HOME/start.jar --list-modules=* 42 attribute $ java -jar $JETTY_HOME/start.jar --add-module=demos 975 to $ java -jar $JETTY_HOME/start.jar --add-module=demos 050
Set the $ java -jar $JETTY_HOME/start.jar --add-module=demos 980 property $ java -jar $JETTY_HOME/start.jar --add-module=demos 975 to $ java -jar $JETTY_HOME/start.jar --add-module=demos 050

Method 1 will only affect the current webapp. Method 2 will affect all webapps deployed to the same Server instance. Method 3 will affect all webapps deployed in the same JVM.

By default, Jetty will wait a maximum of 60 seconds for all of the scanning threads to complete. You can set this to a higher or lower number of seconds by doing one of the following:

Set the context attribute $ java -jar $JETTY_HOME/start.jar --add-module=demos 983
Set the $ java -jar $JETTY_HOME/start.jar --list-modules=* 42 attribute $ java -jar $JETTY_HOME/start.jar --add-module=demos 983
Set the $ java -jar $JETTY_HOME/start.jar --add-module=demos 980 property $ java -jar $JETTY_HOME/start.jar --add-module=demos 983

Method 1 will only affect the current webapp. Method 2 will affect all webapps deployed to the same Server instance. Method 3 will affect all webapps deployed in the same JVM.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 class can exist in: the container’s classpath, the webapp’s

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

99 directory, the webapp’s

$ java -jar $JETTY_HOME/start.jar

01 jars, or any external extraClasspath that you have configured on the webapp.

The Jakarta Servlet Specification does not define any order in which a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 must be called when the webapp starts. By default, Jetty will call them in the following order:

ServletContainerInitializers from the container’s classpath
ServletContainerInitializers from $ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 99
ServletContainerInitializers from $ java -jar $JETTY_HOME/start.jar 01 jars in the order established in web.xml, or in the order that the SCI is returned by the javax.util.ServiceLoader if there is no ordering.

By default, as according to the Jakarta Servlet Specification, all

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 instances that are discovered are invoked.

Sometimes, depending on your requirements, you may need to prevent some being called at all.

In this case, you can define the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

995 context attribute.

This is a regular expression that defines patterns of classnames that you want to exclude. Here’s an example of setting the context attribute in a context XML file:

$ java -jar $JETTY_HOME/start.jar

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

In this example we exclude all

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 instances in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

998, and the specific class

$ java -jar $JETTY_HOME/start.jar --add-module=demos

999.

It is possible to use exclusion and ordering together to control

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 invocation - the exclusions will be applied before the ordering.

If you need

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 classes called in a specific order, you can use the context attribute

$ java -jar $JETTY_HOME/start.jar

002. Set it to a list of comma separated

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 class names in the order that you want them applied.

You may optionally use the wildcard character

$ java -jar $JETTY_HOME/start.jar

004 once in the list. It will match all

$ java -jar $JETTY_HOME/start.jar --add-module=demos

960 classes not explicitly named in the list.

Here is an example context XML file that ensures the

$ java -jar $JETTY_HOME/start.jar

006 will be called first, followed by the

$ java -jar $JETTY_HOME/start.jar

007, then all other SCIs:

$ java -jar $JETTY_HOME/start.jar

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

Jetty supports JSP via the

$ java -jar $JETTY_HOME/start.jar

009 modules, which are based on Apache Jasper:

$ java -jar $JETTY_HOME/start.jar

Logging has been bridged to Jetty logging, so you can enable logging for the

$ java -jar $JETTY_HOME/start.jar

010 package, subpackages and classes as usual.

The

$ java -jar $JETTY_HOME/start.jar

011 is the servlet responsible for serving JSPs.

It is configured as the default jsp servlet in the

$ java -jar $JETTY_HOME/start.jar

012 file. Notice that Jetty identifies the jsp servlet by the presence of the

$ java -jar $JETTY_HOME/start.jar

013 attribute in the

$ java -jar $JETTY_HOME/start.jar

014 declaration.

That file maps the

$ java -jar $JETTY_HOME/start.jar

011 to the following partial urls:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE 93
$ java -jar $JETTY_HOME/start.jar 017
$ java -jar $JETTY_HOME/start.jar 018
$ java -jar $JETTY_HOME/start.jar 019
$ java -jar $JETTY_HOME/start.jar 020
$ java -jar $JETTY_HOME/start.jar 021
$ java -jar $JETTY_HOME/start.jar 022
$ java -jar $JETTY_HOME/start.jar 023

You can change to a different servlet, change or add

$ java -jar $JETTY_HOME/start.jar

024s or add extra

$ java -jar $JETTY_HOME/start.jar

025s in your

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 file.

Here’s an example of adding an

$ java -jar $JETTY_HOME/start.jar

024 to augment the definitions from the standard

$ java -jar $JETTY_HOME/start.jar

028 file:

$ java -jar $JETTY_HOME/start.jar

1 This identifies this servlet as the jsp servlet to Jetty. 2 This identifies this declaration as augmenting the already-defined servlet called

$ java -jar $JETTY_HOME/start.jar

029. 3 This init param controls whether the jsp servlet retains the

$ java -jar $JETTY_HOME/start.jar

030 files generated during jsp compilation. 4 This sets the value of the init param

Another element you might consider adding to the default setup is

$ java -jar $JETTY_HOME/start.jar

031:

$ java -jar $JETTY_HOME/start.jar

1 This identifies this servlet as the jsp servlet to Jetty. 2 This identifies this declaration as augmenting the already-defined servlet called

$ java -jar $JETTY_HOME/start.jar

029. 3 By default, the jsp servlet does not support async.

There are many configuration parameters for the Apache Jasper JSP Servlet, here are some of them:

Table 5. JSP Servlet Parameters init param Description Default

$ java -jar $JETTY_HOME/start.jar

028

checkInterval

If non-zero and

$ java -jar $JETTY_HOME/start.jar

034 is

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050, background jsp recompilation is enabled. This value is the interval in seconds between background recompile checks.

–

classpath

The classpath is dynamically generated if the context has a URL classloader. The

$ java -jar $JETTY_HOME/start.jar

036 context attribute is used to add to the classpath, but if this is not set, this

$ java -jar $JETTY_HOME/start.jar

037 configuration item is added to the classpath instead.`

–

classdebuginfo

Include debugging info in class file.

true

–

compilerClassName

If not set, defaults to the Eclipse jdt compiler.

–

compiler

Used if the Eclipse jdt compiler cannot be found on the classpath. It is the classname of a compiler that Ant should invoke.

–

compilerTargetVM

Target vm to compile for.

1.8

compilerSourceVM

Sets source compliance level for the jdt compiler.

1.8

development

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298 recompilation checks occur at the frequency governed by

$ java -jar $JETTY_HOME/start.jar

039.

true

–

displaySourceFragment

Should a source fragment be included in exception messages

true

–

dumpSmap

Dump SMAP JSR45 info to a file.

false

–

enablePooling

Determines whether tag handler pooling is enabled.

true

–

engineOptionsClass

Allows specifying the Options class used to configure Jasper. If not present, the default EmbeddedServletOptions will be used.

–

errorOnUseBeanInvalidClassAttribute

Should Jasper issue an error when the value of the class attribute in an useBean action is not a valid bean class

true

–

fork

Only relevant if you use Ant to compile JSPs: by default Jetty will use the Eclipse jdt compiler.

true

genStrAsCharArray

Option for generating Strings as char arrays.

false

–

ieClassId

The class-id value to be sent to Internet Explorer when using tags.

clsid:8AD9C840-044E-11D1-B3E9-00805F499D93

–

javaEncoding

Pass through the encoding to use for the compilation.

UTF8

–

jspIdleTimeout

The amount of time in seconds a JSP can be idle before it is unloaded. A value of zero or less indicates never unload.

-1

–

keepgenerated

Do you want to keep the generated Java files around?

true

–

mappedFile

Support for mapped Files. Generates a servlet that has a print statement per line of the JSP file

true

–

maxLoadedJsps

The maximum number of JSPs that will be loaded for a web application. If more than this number of JSPs are loaded, the least recently used JSPs will be unloaded so that the number of JSPs loaded at any one time does not exceed this limit. A value of zero or less indicates no limit.

-1

–

modificationTestInterval

$ java -jar $JETTY_HOME/start.jar

040, interval between recompilation checks, triggered by a request.

–

quoteAttributeEL

When EL is used in an attribute value on a JSP page, should the rules for quoting of attributes described in JSP.1.6 be applied to the expression

true

recompileOnFail

If a JSP compilation fails should the modificationTestInterval be ignored and the next access trigger a re-compilation attempt? Used in development mode only and is disabled by default as compilation may be expensive and could lead to excessive resource usage.

false

–

scratchDir

Directory where servlets are generated. The default is the value of the context attribute

$ java -jar $JETTY_HOME/start.jar

041, or the system property

$ java -jar $JETTY_HOME/start.jar

042 if the context attribute is not set.

–

strictQuoteEscaping

Should the quote escaping required by section JSP.1.6 of the JSP specification be applied to scriplet expression.

true

suppressSmap

Generation of SMAP info for JSR45 debugging.

false

–

trimSpaces

Should template text that consists entirely of whitespace be removed from the output [true], replaced with a single space [single] or left unchanged [false]? Note that if a JSP page or tag file specifies a trimDirectiveWhitespaces value of true, that will take precedence over this configuration setting for that page/tag. trimmed?

false

–

xpoweredBy

Generate an X-Powered-By response header.

false

If the value you set doesn’t take effect, try using all lower case instead of camel case, or capitalizing only some of the words in the name, as Jasper is inconsistent in its parameter naming strategy.

The JavaServer Pages Standard Tag Library [JSTL] is part of the Jetty distribution, and is available via the

$ java -jar $JETTY_HOME/start.jar

043 modules:

$ java -jar $JETTY_HOME/start.jar

When enabled, Jetty will make the JSTL tags available for your webapps.

If you want to use JSF with your webapp, you should copy the relevant jars from your implementation of choice into your

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory, ideally into

$ java -jar $JETTY_HOME/start.jar

045. If that directory does not exist, enable the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

80 module, which will create the directory and ensure all jars within it are put onto the container classpath.

Then you will need to tell Jetty which of those jars contains the

$ java -jar $JETTY_HOME/start.jar

047 files. To accomplish that, you need to specify either the name of the file or a pattern that matches the name/s of the file/s as the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

962 context attribute. You will need to preserve the existing value of the attribute, and add in your extra pattern.

Here’s an example of using a context xml file to add in a pattern to match files starting with

$ java -jar $JETTY_HOME/start.jar

049, which contain the

$ java -jar $JETTY_HOME/start.jar

047 files:

$ java -jar $JETTY_HOME/start.jar

1 Configures a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

174, which is the Jetty component that represents a standard Servlet web application. 2 Specifies a context attribute. 3 Specifies the name of the context attribute. 4 Adds the additional pattern

$ java -jar $JETTY_HOME/start.jar

052 to those already existing.

For each specific Jakarta EE environment there is a specific

$ java -jar $JETTY_HOME/start.jar

053 module that you must enable in order to use JNDI resources in your webapp:

For Java EE 8, $ java -jar $JETTY_HOME/start.jar 054
For Java EE 9, $ java -jar $JETTY_HOME/start.jar 055
For Java EE 10, $ java -jar $JETTY_HOME/start.jar 056

If you have already enabled an module suitable for your environment, an appropriate

$ java -jar $JETTY_HOME/start.jar

053 module will already have been enabled and you do not need to explicitly enable a

$ java -jar $JETTY_HOME/start.jar

053 module.

If you have extra jars associated with your JNDI resources, eg database drivers etc, that are not located inside your webapp then you must ensure they are on either the container classpath or a Jakarta EE environment classpath. You can enable the

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

80 module and place your jars in

$ java -jar $JETTY_HOME/start.jar

061 to make them visible on the container classpath. To make them visible on an environment classpath you should create a custom, environment-specific module.

You can now declare JNDI resources and reference them within your webapps.

You must declare the objects you want bound into the environment so that you can then hook them into your webapp via

$ java -jar $JETTY_HOME/start.jar

062,

$ java -jar $JETTY_HOME/start.jar

063 and

$ java -jar $JETTY_HOME/start.jar

064 in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191,

$ java -jar $JETTY_HOME/start.jar

066 or

$ java -jar $JETTY_HOME/start.jar

067.

You make these declarations in Jetty XML files that are either external or internal to your webapp. A server or context XML file is external to your webapp. The special

$ java -jar $JETTY_HOME/start.jar --add-module=demos

194 file is internal to your webapp. See the section on for more information on how to choose in which XML file to place your declarations.

Regardless of its location, the XML file contains declarations of JNDI resources that can be referenced later within your webapp.

The declarations are new instances of the following types:

Declarations of each of these types follow a similar pattern:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

1 Defines a resource to Jetty. 2 Specifies the of the resource. 3 Specifies the name of the resource which will be looked up by the webapp relative to the

$ java -jar $JETTY_HOME/start.jar

069 or

$ java -jar $JETTY_HOME/start.jar

070 namespace. 4 Specifies the value of the resource.

Sometimes it is useful to pass configuration information to a webapp at runtime that you either cannot or cannot conveniently code into a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191

$ java -jar $JETTY_HOME/start.jar

072. In such cases, you can use the

$ java -jar $JETTY_HOME/start.jar

073 class, and optionally even override an entry of the same name in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191.

Here’s an example that defines the equivalent of an

$ java -jar $JETTY_HOME/start.jar

062 called

$ java -jar $JETTY_HOME/start.jar

076 with value

$ java -jar $JETTY_HOME/start.jar

077 that overrides an

$ java -jar $JETTY_HOME/start.jar

072 declaration of the same name in web.xml:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

1 Define an

$ java -jar $JETTY_HOME/start.jar

079 that corresponds to an

$ java -jar $JETTY_HOME/start.jar

072. 2 at the JVM level. 3 The name of the entry, corresponding to a lookup by the webapp of

$ java -jar $JETTY_HOME/start.jar

081. 4 The value of the entry, in this case the integer value

$ java -jar $JETTY_HOME/start.jar

077. 5

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298 means to override the value of an

$ java -jar $JETTY_HOME/start.jar

072 of the same name in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191.

Note that if you don’t want to override the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 value, simply omit the last argument, or set it to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050.

The Servlet Specification allows binding only the following object types to an

$ java -jar $JETTY_HOME/start.jar

062:

java.lang.String
java.lang.Integer
java.lang.Float
java.lang.Double
java.lang.Long
java.lang.Short
java.lang.Character
java.lang.Byte
java.lang.Boolean

Jetty is a little more flexible and allows you to also bind:

custom POJOs
$ java -jar $JETTY_HOME/start.jar 089
$ java -jar $JETTY_HOME/start.jar 090

Be aware that if you take advantage of this feature, your web application is not portable.

You can configure any type of resource that you want to refer to in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 via a

$ java -jar $JETTY_HOME/start.jar

063 or

$ java -jar $JETTY_HOME/start.jar

093 by using the

$ java -jar $JETTY_HOME/start.jar

094 type of naming entry.

You provide the scope, the name of the object [relative to

$ java -jar $JETTY_HOME/start.jar

and a POJO,

$ java -jar $JETTY_HOME/start.jar

096 or

$ java -jar $JETTY_HOME/start.jar

097 instance.

This example configures a Derby DataSource named

$ java -jar $JETTY_HOME/start.jar

098:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

This would be linked into the webapp’s JNDI namespace via an entry in a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 like so:

$ java -jar $JETTY_HOME/start.jar

When configuring Resources, ensure that the type of object you configure matches the type of object you expect to look up in

$ java -jar $JETTY_HOME/start.jar

070. For database connection factories, this means that the object you register as a Resource must implement the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

20 interface.

Also note that the J2EE Specification recommends storing DataSources relative to

$ java -jar $JETTY_HOME/start.jar

102 and thus looked up by the application as

$ java -jar $JETTY_HOME/start.jar

103. Eg The Datasource bound in Jetty as

$ java -jar $JETTY_HOME/start.jar

104 would be looked up by the application as

$ java -jar $JETTY_HOME/start.jar

105

Jetty can bind any implementation of the JMS destinations and connection factories.

Here is an example of binding an ActiveMQ in-JVM connection factory:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

The corresponding entry in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 to bind the ConnectionFactory into the webapp’s JNDI namespace would be:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

The J2EE Specification recommends storing JMS connection factories under

$ java -jar $JETTY_HOME/start.jar

107. Eg The ConnectionFactory bound in Jetty as

$ java -jar $JETTY_HOME/start.jar

108 would be looked up by the application as

$ java -jar $JETTY_HOME/start.jar

109.

To configure access to

$ java -jar $JETTY_HOME/start.jar

110 from within a webapp, declare an

$ java -jar $JETTY_HOME/start.jar

094 with an

$ java -jar $JETTY_HOME/start.jar

112 that will hold the mail configuration and create the instance of the

$ java -jar $JETTY_HOME/start.jar

113 when it is referenced:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

1 Use the

$ java -jar $JETTY_HOME/start.jar

114 class to hold the configuration. 2 Set the username for the mail instance. 3 Set the password for the mail instance — use the to obfuscate the password. 4 Set all other applicable properties.

The webapp performs a lookup for

$ java -jar $JETTY_HOME/start.jar

115 at runtime and obtains a

$ java -jar $JETTY_HOME/start.jar

110 that has the correct configuration to permit it to send email via SMTP.

Jetty does not provide the

$ java -jar $JETTY_HOME/start.jar

117 and

$ java -jar $JETTY_HOME/start.jar

118 jars.

Note also that the J2EE Specification recommends storing JavaMail connection factories under

$ java -jar $JETTY_HOME/start.jar

119. Eg The

$ java -jar $JETTY_HOME/start.jar

120 bound to jetty as

$ java -jar $JETTY_HOME/start.jar

121 would be looked up by the application as

$ java -jar $JETTY_HOME/start.jar

122.

To perform distributed transactions with your resources, a transaction manager that supports the JTA interfaces is required. The transaction manager is looked up by the application as

$ java -jar $JETTY_HOME/start.jar

123.

Jetty does not ship with a JTA manager, but does provide the infrastructure to plug in the JTA manager of your choice.

If your JTA library’s implementation of

$ java -jar $JETTY_HOME/start.jar --list-modules=*

16 implements

$ java -jar $JETTY_HOME/start.jar

096, then you should use the

$ java -jar $JETTY_HOME/start.jar

126 object in a to register it in JNDI:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

If your JTA library’s implementation of

$ java -jar $JETTY_HOME/start.jar --list-modules=*

16 does not implement

$ java -jar $JETTY_HOME/start.jar

096, then you should use the Jakarta EE specific Jetty class to register it in JNDI:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

Jetty will automatically bind this JTA manager to the webapp’s JNDI namespace at

$ java -jar $JETTY_HOME/start.jar

123.

Usually, the name you provide for the

$ java -jar $JETTY_HOME/start.jar

094 is the same name you reference in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191. This ensures that the two are linked together and thus accessible to your webapp.

However, if the names cannot be the same, then it is possible to effectively alias one to another using an

$ java -jar $JETTY_HOME/start.jar

132.

Supposing you have a declaration for a Datasource named

$ java -jar $JETTY_HOME/start.jar

133 in a Jetty context XML file, but your web.xml wants to link to a

$ java -jar $JETTY_HOME/start.jar

134 named

$ java -jar $JETTY_HOME/start.jar

135, and you cannot edit the web.xml. You can create a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

194 file with an

$ java -jar $JETTY_HOME/start.jar

137 that ties together the names

$ java -jar $JETTY_HOME/start.jar

133 and

$ java -jar $JETTY_HOME/start.jar

135:

The context XML file declares

$ java -jar $JETTY_HOME/start.jar

133:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 refers to it as

$ java -jar $JETTY_HOME/start.jar

135:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

Create a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

194 file with a

$ java -jar $JETTY_HOME/start.jar

132 to link these names together:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

1 The name as referenced in the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 file. 2 The name as referenced in the context XML file.

You can define naming resources in three places:

Server XML file

Naming resources defined in a server XML file are at the JVM,

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

90 or environment level. Note that the classes for the resource must be visible at the point in time that the XML executes. For example, environment level resources should be declared in an XML file that is referenced by a custom module that contains an

$ java -jar $JETTY_HOME/start.jar

147 clause at the matching environment level to ensure the classpath for that environment is available.

Context XML file

Entries in a context XML file should be at the level of the webapp to which they apply [it is possible to use a less strict scoping level of Server or JVM, but not recommended]. As a context XML file executes before the webapp’s classes are available, the classes for your resource must be external to the webapp and on either the container or environment classpath.

WEB-INF/jetty-env.xml

Naming resources in a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

194 file are to the webapp in which the file resides. The resources defined here may use classes from inside your webapp.

Naming resources within Jetty belong to different scopes, in increasing order of restrictiveness:

JVM scope: The name is unique across the JVM instance, and is visible to all application code. This scope is represented by a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

528 first parameter to the resource declaration. For example:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

1 Empty first arg equates to JVM scope for the object bound to name

$ java -jar $JETTY_HOME/start.jar

150.

Environment scope: The name is unique within a Jetty environment. It is represented by referencing the name of the Jakarta EE environment as the first parameter to the resource declaration. For example:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

Webapp scope: The name is unique to the

$ java -jar $JETTY_HOME/start.jar

151 instance, and is only visible to that application. This scope is represented by referencing the instance as the first parameter to the resource declaration. For example:

wiki.xml

$ java -jar $JETTY_HOME/start.jar

JAAS implements a Java version of the standard Pluggable Authentication Module [PAM] framework.

JAAS can be used for two purposes:

for authentication of users, to reliably and securely determine who is currently executing Java code, regardless of whether the code is running as an application, an applet, a bean, or a servlet
for authorization of users to ensure they have the access control rights [permissions] required to do the actions performed

JAAS authentication is performed in a pluggable fashion. This permits applications to remain independent from underlying authentication technologies. New or updated authentication technologies can be plugged under an application without requiring modifications to the application itself.

See Java Authentication and Authorization Service [JAAS] Reference Guide for more information about JAAS.

The Jetty JAAS support aims to dictate as little as possible whilst providing a sufficiently flexible infrastructure to allow users to drop either one of the , or their own custom LoginModules.

Enable the

$ java -jar $JETTY_HOME/start.jar

153 module appropriate for your EE platform:

$ java -jar $JETTY_HOME/start.jar

The configurable items in the resulting

$ java -jar $JETTY_HOME/start.jar

154 file are:

jetty.jaas.login.conf

This is the location of the file that will be referenced by the system property

$ java -jar $JETTY_HOME/start.jar

155: Jetty sets this system property for you based on the value of this property. The value of this property is assumed to be relative to

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34. The default value is

$ java -jar $JETTY_HOME/start.jar

157, which resolves to

$ java -jar $JETTY_HOME/start.jar

158. If you don’t want to put your login module configuration file here, you can change this property to point to where it is.

See more about the contents of this file in the section.

The

$ java -jar $JETTY_HOME/start.jar

159 in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 will be used to identify the

$ java -jar $JETTY_HOME/start.jar

161 declaration that integrates JAAS with Jetty.

For example, this

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191 contains a realm called

$ java -jar $JETTY_HOME/start.jar

163:

$ java -jar $JETTY_HOME/start.jar

1 The name of the realm, which must be identical to the name of an

$ java -jar $JETTY_HOME/start.jar

161 declaration.

We now need to declare an

$ java -jar $JETTY_HOME/start.jar

161 that references the realm name of

$ java -jar $JETTY_HOME/start.jar

163. Here’s an example of a suitable XML snippet:

$ java -jar $JETTY_HOME/start.jar

1 The name is the same as that declared in the

$ java -jar $JETTY_HOME/start.jar

159 in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

191. 2 The name that identifies a set of

$ java -jar $JETTY_HOME/start.jar

169 configurations that comprise the identified in the

$ java -jar $JETTY_HOME/start.jar

170 property of the .

The

$ java -jar $JETTY_HOME/start.jar

161 can be declared in a couple of different places, pick whichever suits your purposes best:

If you have more than one webapp that you would like to use the same security infrastructure, then you can declare your
$ java -jar $JETTY_HOME/start.jar 161 as a bean that is added to the
java.lang.AssertionError: Target Dir Expected: path is directory but: path does not exist 90. The file in which you declare this needs to be on Jetty’s execution path. The recommended procedure is to create a file in your $ java -jar $JETTY_HOME/start.jar 175 directory and then ensure it is on the classpath either by adding it to the Jetty , or more conveniently to a . Here’s an example of this type of XML file: $ java -jar $JETTY_HOME/start.jar 71
Alternatively, if you want to use JAAS with a specific webapp only, you declare your $ java -jar $JETTY_HOME/start.jar 161 in a context XLM file specific to that webapp: $ java -jar $JETTY_HOME/start.jar 72

We now need to setup the contents of the file we specified as the

$ java -jar $JETTY_HOME/start.jar

170 property when we . Refer to the syntax rules of this file for a full description.

Remembering the example we set up , the contents of the

$ java -jar $JETTY_HOME/start.jar

179 file could look as follows:

$ java -jar $JETTY_HOME/start.jar

1 The name of the configuration exactly as specified in your

$ java -jar $JETTY_HOME/start.jar

161 declaration. 2 The first

$ java -jar $JETTY_HOME/start.jar

181 declaration, containing the classname of the

$ java -jar $JETTY_HOME/start.jar

181 and its configuration properties. 3 A second

$ java -jar $JETTY_HOME/start.jar

181 declaration. You can provide as many

$ java -jar $JETTY_HOME/start.jar

181 alternatives as you like, with a minimum of one. Refer to the JAAS documentation for more information on the standard configuration properties, and how JAAS interprets this file.

$ java -jar $JETTY_HOME/start.jar 185
$ java -jar $JETTY_HOME/start.jar 186
$ java -jar $JETTY_HOME/start.jar 187
$ java -jar $JETTY_HOME/start.jar 188

The

$ java -jar $JETTY_HOME/start.jar

185 stores user passwords and roles in a database accessed via JDBC calls. You can configure the JDBC connection information, as well as the names of the table and columns storing the username and credential, and the names of the table and columns storing the roles.

$ java -jar $JETTY_HOME/start.jar

1 The name of the configuration. 2 The name of the

$ java -jar $JETTY_HOME/start.jar

181 class. 3 A standard JAAS flag making successful authentication via this

$ java -jar $JETTY_HOME/start.jar

181 mandatory. 4 The JDBC url used to connect to the database. 5 The name of the JDBC user to use for the connection. 6 The name of the JDBC Driver class. 7 The name of the table holding the user authenication information. 8 The name of the column holding the user name. 9 The name of the column holding the user credential. 10 The name of the table holding the user authorization information. 11 The name of the column holding the user name. 12 The name of the column holding the user role.

The properties 7-12 are used to format the following queries:

$ java -jar $JETTY_HOME/start.jar

Credential and role information is lazily read from the database when a previously unauthenticated user requests authentication. Note that this information is only cached for the length of the authenticated session. When the user logs out or the session expires, the information is flushed from memory.

Note that passwords can be stored in the database in plain text or encoded formats — see the note on "Passwords/Credentials" above.

Similar to the

$ java -jar $JETTY_HOME/start.jar

185, but using a

$ java -jar $JETTY_HOME/start.jar --list-modules=*

20 to connect to the database instead of a JDBC driver. The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

20 is obtained at runtime by performing a JNDI lookup on

$ java -jar $JETTY_HOME/start.jar

195.

A sample login module configuration for this

$ java -jar $JETTY_HOME/start.jar

181:

$ java -jar $JETTY_HOME/start.jar

1 The name of the configuration. 2 The name of the

$ java -jar $JETTY_HOME/start.jar

181 class. 3 A standard JAAS flag making successful authentication via this

$ java -jar $JETTY_HOME/start.jar

181 mandatory. 4 The JNDI name, relative to

$ java -jar $JETTY_HOME/start.jar

199 to lookup to obtain the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

20. 5 The name of the table holding the user authenication information. 6 The name of the column holding the user name. 7 The name of the column holding the user credential. 8 The name of the table holding the user authorization information. 9 The name of the column holding the user name. 10 The name of the column holding the user role.

With this login module implementation, the authentication and role information is read from a property file.

$ java -jar $JETTY_HOME/start.jar

1 The name of the configuration. 2 The name of the

$ java -jar $JETTY_HOME/start.jar

181 class. 3 A standard JAAS flag making successful authentication via this

$ java -jar $JETTY_HOME/start.jar

181 mandatory. 4 The location of a properties file containing the authentication and authorization information.

The property file must be of the format:

$ java -jar $JETTY_HOME/start.jar

Here’s an example:

$ java -jar $JETTY_HOME/start.jar

The contents of the file are fully read in and cached in memory the first time a user requests authentication.

The

$ java -jar $JETTY_HOME/start.jar

203 uses LDAP to access authentication and authorization information stored in a directory. The LDAP connection information and structure of the authentication/authorization data can be configured.

Here’s an example:

$ java -jar $JETTY_HOME/start.jar

1 The name of the configuration. 2 The name of the

$ java -jar $JETTY_HOME/start.jar

181 class. 3 A standard JAAS flag making successful authentication via this

$ java -jar $JETTY_HOME/start.jar

181 mandatory. 4 The name of the context factory to use for the LDAP connection. 5 The hostname for the LDAP connection. Optional. 6 The port for the LDAP connection. Optional. 7 The caller security Principal. Optional. 8 The caller security credential. Optional. 9 The security level for the LDAP connection environment. Optional. 10 If true, use

$ java -jar $JETTY_HOME/start.jar

206 instead of

$ java -jar $JETTY_HOME/start.jar

207 for the connection url. 11 The distinguished name of the directory to search for user information. 12 The name of the attribute for the user roles. 13 The name of the attribute for the user id. 14 The name of the attribute for the user password. 15 The

$ java -jar $JETTY_HOME/start.jar

208 for users. 16 The distinguished name of the directory to search for role information. 17 The name of the attribute for roles. 18 The name of the attribute storing the user for the roles

$ java -jar $JETTY_HOME/start.jar

208. 19 The name of the

$ java -jar $JETTY_HOME/start.jar

208 for roles. 20 If true, the authentication proceeds on the basis of a successful LDAP binding using the username and credential provided by the user. If false, then authentication proceeds based on username and password information retrieved from LDAP. 21 If true, failed login attempts are logged on the server.

Enabling this module allows Jetty to utilize authentication modules that implement the Jakarta Authentication [JASPI] specification. JASPI provides an SPI [Service Provider Interface] for pluggable, portable, and standardized authentication modules. Compatible modules are portable between servers that support the JASPI specification. This module provides a bridge from Jakarta Authentication to the Jetty Security framework.

Only modules conforming to the "Servlet Container Profile" with the ServerAuthModule interface within the JakartaAuthentication are supported. These modules must be configured before start-up. Operations for runtime registering or de-registering authentication modules are not supported.

Enable the

$ java -jar $JETTY_HOME/start.jar

211 module:

$ java -jar $JETTY_HOME/start.jar

Activate either the

$ java -jar $JETTY_HOME/start.jar

213 or

$ java -jar $JETTY_HOME/start.jar

214 module, whichever matches your EE platform version.

$ java -jar $JETTY_HOME/start.jar

You can then register a

$ java -jar $JETTY_HOME/start.jar

215 onto the static

$ java -jar $JETTY_HOME/start.jar

216 obtained with

$ java -jar $JETTY_HOME/start.jar

217. This registration can be done in the XML configuration file which will be copied to

$ java -jar $JETTY_HOME/start.jar

218 when the module is enabled.

The

$ java -jar $JETTY_HOME/start.jar

219 and

$ java -jar $JETTY_HOME/start.jar

220 modules illustrate setting up HTTP Basic Authentication using the EE9 and EE 10 Jakarta Authentication modules that come packaged with Jetty.

The following example uses Jetty’s EE 10 implementation of

$ java -jar $JETTY_HOME/start.jar

215 to register a

$ java -jar $JETTY_HOME/start.jar

222 directly.

$ java -jar $JETTY_HOME/start.jar

Other custom or 3rd party modules that are compatible with the

$ java -jar $JETTY_HOME/start.jar

222 interface in JASPI can be registered in the same way.

To integrate with Jetty authentication mechanisms you must add a

$ java -jar $JETTY_HOME/start.jar

224 to your context. The

$ java -jar $JETTY_HOME/start.jar

224 provides a way for you to obtain a

$ java -jar $JETTY_HOME/start.jar

226 from a username and credentials. JASPI can interact with this Jetty

$ java -jar $JETTY_HOME/start.jar

224 by using the

$ java -jar $JETTY_HOME/start.jar

228.

The

$ java -jar $JETTY_HOME/start.jar

229 and

$ java -jar $JETTY_HOME/start.jar

230 do not require use of a Jetty

$ java -jar $JETTY_HOME/start.jar

224. The principal from the

$ java -jar $JETTY_HOME/start.jar

229 will be used directly with the

$ java -jar $JETTY_HOME/start.jar

233 to produce a

$ java -jar $JETTY_HOME/start.jar

226.

Jetty provides an implementation of the

$ java -jar $JETTY_HOME/start.jar

216 interface which is used to register

$ java -jar $JETTY_HOME/start.jar

236. This can be replaced by a custom implementation by adding a custom module which provides

$ java -jar $JETTY_HOME/start.jar

237. This custom module must reference an XML file which sets a new instance of the

$ java -jar $JETTY_HOME/start.jar

216 with the static method

$ java -jar $JETTY_HOME/start.jar

239. For an example of this see the

$ java -jar $JETTY_HOME/start.jar

240 module, which provides the default implementation used by Jetty.

$ java -jar $JETTY_HOME/start.jar

Monitoring and management of a Jetty server is important because it allows you to monitor the status of the server ["Is the server processing requests?"] and to manage — i.e. read and possibly change — its configuration.

The ability to read and change the Jetty configuration is very important for troubleshooting Jetty — please refer to the for more information.

Jetty relies on the Java Management Extensions [JMX] APIs included in OpenJDK to provide monitoring and management.

The JMX APIs support a JVM-local

$ java -jar $JETTY_HOME/start.jar

241, accessible only from within the JVM itself [or by tools that can attach to a running JVM], and a way to expose the

$ java -jar $JETTY_HOME/start.jar

241 to remote clients via Java’s RMI [Remote Method Invocation].

As with many other Jetty features, local JMX support is enabled with the :

$ java -jar $JETTY_HOME/start.jar

With the

$ java -jar $JETTY_HOME/start.jar

14 Jetty module enabled, Jetty components will be exported as JMX MBeans to the JVM platform

$ java -jar $JETTY_HOME/start.jar

241, so that they can be accessed by JMX compliant tools.

Each Jetty component will export to its correspondent MBean relevant configuration parameters, so that a JMX tool can read and possibly change the component configuration through the MBean.

Note that the Jetty MBeans are registered into the platform

$ java -jar $JETTY_HOME/start.jar

241, but are not available to remote clients: they are local to the JVM.

This configuration is useful when you develop and test your Jetty server locally.

JMX compliant tools such as Java Mission Control [JMC] can be started locally on your machine and can attach to other JVMs running on your machine, showing you the registered MBeans among which you will find the Jetty MBeans.

Enabling only the local JMX support is the most secure option for monitoring and management, but only users that have local access to the JVM will be able to browse the MBeans. If you need to access the MBeans from a remote machine, read .

There are two ways to configure a Jetty server so that it is possible to access the JVM platform MBeans from remote clients:

Use the $ java -jar $JETTY_HOME/start.jar 247 and related system properties when starting Jetty. Unfortunately, this solution does not work well with firewalls, and will not be discussed further.
Use the $ java -jar $JETTY_HOME/start.jar 15 Jetty module.

Both ways use Java’s Remote Method Invocation [RMI] to communicate between the client and the server.

Refresher: How RMI Works

A server application that wants to make an object available to remote clients must export the object.

Exporting an object creates an RMI stub that contains the host/port of the RMI server that accepts incoming invocations from clients and forwards them to the object. During the creation of the RMI stub, the host stored in the RMI stub is retrieved from the local name resolution system [for example, in Linux, from

$ java -jar $JETTY_HOME/start.jar

21].

The RMI stub is then sent, along with a name that uniquely identifies the object, to the RMI registry. The RMI registry is a service that maps names to RMI stubs; it may be external to both clients and server, although often it is part of the server JVM.

When a client application wants to connect to the server object using RMI, it first connects to the RMI registry to download the RMI stub for the RMI server; recall that the RMI stub contains the host/port to connect to the RMI server. Then, the client uses the RMI stub to connect to the RMI server, typically to a host/port that may be different from the RMI registry host/port [in particular, by default the RMI server port will be different from the RMI registry port].

Remote access to the platform MBeans, and therefore the Jetty MBeans, is enabled by the

$ java -jar $JETTY_HOME/start.jar

15 Jetty module:

$ java -jar $JETTY_HOME/start.jar

This command creates the

$ java -jar $JETTY_HOME/start.jar

251 file:

$ java -jar $JETTY_HOME/start.jar

Enabling the

$ java -jar $JETTY_HOME/start.jar

15 module transitively enables the as well.

The configuration for the RMI registry and the RMI server is specified by a

$ java -jar $JETTY_HOME/start.jar

254. The string format of an RMI

$ java -jar $JETTY_HOME/start.jar

254 is the following:

$ java -jar $JETTY_HOME/start.jar

Below you can find examples of

$ java -jar $JETTY_HOME/start.jar

254s:

$ java -jar $JETTY_HOME/start.jar

The default

$ java -jar $JETTY_HOME/start.jar

254 configured by the

$ java -jar $JETTY_HOME/start.jar

15 module is the following:

$ java -jar $JETTY_HOME/start.jar

With the default configuration, only clients that are local to the server machine can connect to the RMI registry and RMI server - this is done for security reasons. However, even with this local-only configuration, it would still be possible to access the MBeans from remote using an SSH tunnel, as explained in .

By specifying an appropriate

$ java -jar $JETTY_HOME/start.jar

254, you can fine tune the network address the RMI registry and the RMI server bind to, and the ports that the RMI registry and the RMI server listen to. The RMI server and RMI registry hosts and ports can be the same [as in the default configuration] because RMI is able to multiplex traffic arriving to one port to multiple RMI objects.

If you need to allow JMX remote access through a firewall, you must open both the RMI registry and the RMI server ports. The default configuration simplifies the firewall configuration because you only need to open port

$ java -jar $JETTY_HOME/start.jar

260.

When Jetty is started with the

$ java -jar $JETTY_HOME/start.jar

15 module enabled, the RMI stub of the Jetty component that provides access to the MBeans is exported to the RMI registry.

The RMI stub contains the host/port to connect to the RMI server, but the host is typically the machine host name, not the host specified in the

$ java -jar $JETTY_HOME/start.jar

254 [the latter is only used to specify the network address the RMI server binds to].

To control the host stored in the RMI stub you need to set the system property

$ java -jar $JETTY_HOME/start.jar

17 with the desired value in the module configuration file,

$ java -jar $JETTY_HOME/start.jar

251.

If your client cannot connect to the server, the most common cause is a mismatch between the RMI server host of the

$ java -jar $JETTY_HOME/start.jar

254 and the RMI server host of the RMI stub.

You can customize the RMI server host/port, the RMI registry host/port and the system property

$ java -jar $JETTY_HOME/start.jar

17 by editing the

$ java -jar $JETTY_HOME/start.jar

251 configuration file. Further information about the

$ java -jar $JETTY_HOME/start.jar

15 module configuration can be found .

You can access JMX MBeans on a remote machine when the RMI ports are not open, for example because of firewall policies, but you have SSH access to the machine, using local port forwarding via an SSH tunnel.

In this case you want to configure the

$ java -jar $JETTY_HOME/start.jar

254 that binds the RMI server and the RMI registry to the loopback interface only and to the same port:

$ java -jar $JETTY_HOME/start.jar

You must set the system property

$ java -jar $JETTY_HOME/start.jar

270 so that the RMI stub contains

$ java -jar $JETTY_HOME/start.jar

25 as the host name to connect to. This is, incidentally, the default configuration of the

$ java -jar $JETTY_HOME/start.jar

15 module.

Then you set up the local port forwarding with the SSH tunnel:

$ java -jar $JETTY_HOME/start.jar

Thanks to the local port forwarding of the SSH tunnel, when the client connects to

$ java -jar $JETTY_HOME/start.jar

273 on your local computer, the traffic will be forwarded to

$ java -jar $JETTY_HOME/start.jar

274 and when there, the SSH daemon will forward the traffic to

$ java -jar $JETTY_HOME/start.jar

273 on

$ java -jar $JETTY_HOME/start.jar

274, which is exactly where the RMI server and the RMI registry listens to.

The client first contacts the RMI registry, so it connects to

$ java -jar $JETTY_HOME/start.jar

273 on your local computer; the traffic is forwarded to

$ java -jar $JETTY_HOME/start.jar

274 through the SSH tunnel, connects to the RMI registry and the RMI stub is downloaded to the client.

Then the client uses the RMI stub to connect to the RMI server. The RMI stub contains

$ java -jar $JETTY_HOME/start.jar

25 as the RMI server host because that is what you have configured with the system property

$ java -jar $JETTY_HOME/start.jar

17.

The client will connect again to

$ java -jar $JETTY_HOME/start.jar

273 on your local computer, this time to contact the RMI server; the traffic is forwarded to

$ java -jar $JETTY_HOME/start.jar

274 through the SSH tunnel, arrives to

$ java -jar $JETTY_HOME/start.jar

274 and connects to the RMI server.

The standard

$ java -jar $JETTY_HOME/start.jar

284 class, used by the

$ java -jar $JETTY_HOME/start.jar

15 module to provide remote JMX access to Jetty MBeans, provides several options to authenticate and authorize users. For a complete guide to controlling authentication and authorization in JMX, see the official JMX documentation.

The simplest way to control JMX authentication and authorization is to specify two files: one contains username and password pairs, and the other contains username and permission pairs.

This is achieved by enabling the

$ java -jar $JETTY_HOME/start.jar

286 Jetty module:

$ java -jar $JETTY_HOME/start.jar

Enabling the

$ java -jar $JETTY_HOME/start.jar

286 Jetty module creates the following files:

$ java -jar $JETTY_HOME/start.jar

Then you edit the

$ java -jar $JETTY_HOME/start.jar

288 file, adding the username/password pairs that you need:

$JETTY_BASE/etc/jmxremote.password

$ java -jar $JETTY_HOME/start.jar

You must also edit the

$ java -jar $JETTY_HOME/start.jar

289 file to give permissions to your users:

$JETTY_BASE/etc/jmxremote.access

$ java -jar $JETTY_HOME/start.jar

The above files define user

$ java -jar $JETTY_HOME/start.jar

290 with password

$ java -jar $JETTY_HOME/start.jar

291 to have

$ java -jar $JETTY_HOME/start.jar

292 access, and user

$ java -jar $JETTY_HOME/start.jar

293 with password

$ java -jar $JETTY_HOME/start.jar

294 to have

$ java -jar $JETTY_HOME/start.jar

295 access.

The JMX communication via RMI happens by default in clear-text, but it is possible to secure the JMX communication via RMI with TLS.

If you want to reuse the configuration that you are using for the , you can just enable the

$ java -jar $JETTY_HOME/start.jar

297 Jetty module:

$ java -jar $JETTY_HOME/start.jar

The

$ java -jar $JETTY_HOME/start.jar

298 Jetty module depends on the

$ java -jar $JETTY_HOME/start.jar --add-modules=http

90 Jetty module that in turn requires a KeyStore [read for more information].

The KeyStore must contain a valid certificate signed by a Certification Authority. Having certificates signed by a Certification Authority simplifies by a lot the configuration needed to get the RMI communication over TLS working properly.

The RMI mechanic is the usual one: the RMI client [typically a monitoring console] will connect first to the RMI registry [using TLS], download the RMI stub that contains the address and port of the RMI server to connect to, then connect to the RMI server [using TLS].

This also mean that if the RMI registry and the RMI server are on different hosts, the RMI client must have available the cryptographic material to validate the certificates from both hosts. This is where having certificates signed by a Certification Authority simplifies the configuration: if they are signed by a well known Certification Authority, the client does not need any extra configuration — everything will be handled by the Java runtime.

If the certificates are not signed by a Certification Authority [for example the certificate is self-signed], then you need to specify the TLS system properties that allow RMI [especially when acting as an RMI client] to retrieve the cryptographic material necessary to establish the TLS connection.

When the RMI server exports the

$ java -jar $JETTY_HOME/start.jar

300 it acts as an RMI client towards the RMI registry, and as such you must specify the TLS system properties as detailed below.

You must edit the

$ java -jar $JETTY_HOME/start.jar

301 file and add the TrustStore path and password:

$JETTY_BASE/start.d/jmx-remote-ssl.ini

$ java -jar $JETTY_HOME/start.jar

The TrustStore must contain the certificate you want to trust.

If you are using self-signed certificates, the KeyStore already contains the self-signed certificate and therefore the KeyStore can be used as a TrustStore, and the system properties above can refer to the KeyStore path and password.

JMX compliant tools that offer a graphical user interface also must be started specifying the TrustStore path and password.

$ java -jar $JETTY_HOME/start.jar

There are many cases where you might need to provide credentials such as usernames and passwords to authenticate your access to certain services, for example KeyStore and TrustStore passwords, JDBC credentials, Basic or Digest authentication credentials, etc.

Passwords are typically stored in clear-text in configuration files, because a program such as Jetty reading the configuration file must be able to retrieve the original password to authenticate with the service.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

1 Hit Enter to specify a blank user. 2 Enter the password you want to obfuscate. 3 The obfuscated password. 4 The MD5 checksum of the password.

The

$ java -jar $JETTY_HOME/start.jar

302 tool produced an obfuscated string for the password

$ java -jar $JETTY_HOME/start.jar

303, namely

$ java -jar $JETTY_HOME/start.jar

304 [the prefix

$ java -jar $JETTY_HOME/start.jar

305 must be retained]. The obfuscated string can be de-obfuscated to obtain the original password.

Now you can use the obfuscated password in Jetty configuration files, for example to specify the KeyStore password in

$ java -jar $JETTY_HOME/start.jar --add-module=demos

410 when configuring secure connectors, as explained . For example:

ssl.ini

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Remember that password obfuscation only protects from casual view — it can be de-obfuscated to obtain the original password.

You can also use the obfuscated password in your Java source code.

You can also use obfuscated passwords in Jetty XML files where a clear-text password is usually required. Here is an example, setting an obfuscated password for a JDBC

$ java -jar $JETTY_HOME/start.jar --list-modules=*

15:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

1 Note the usage of

$ java -jar $JETTY_HOME/start.jar

308 to avoid storing the clear-text password in the XML file.

To troubleshoot Jetty when used as a production server, there are two main tools: the Jetty Server Dump and enabling DEBUG level logging.

Jetty is based on components organized as a tree, with the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 instance at the root of the tree.

As explained in the , these components can be exported as JMX MBeans and therefore be accessible from JMX Consoles such as Java Missions Control [JMC].

Being able to take a snapshot of the state of Jetty while it is running is the most useful information that can be attached when reporting an issue. Such state includes:

The thread pool configuration and its current state, including how many threads are in use, and their stack trace.
The TLS configuration.
The I/O configuration and its current state, including the ports Jetty listens to, how many connections are currently open, and he state of each connection, and the state of the request/response handling for each connection.
The INFO : mkdir ${jetty.base}/start.d INFO : server transitively enabled, ini template available with --add-modules=server INFO : logging-jetty transitively enabled INFO : http initialized in ${jetty.base}/start.d/http.ini INFO : resources transitively enabled INFO : threadpool transitively enabled, ini template available with --add-modules=threadpool INFO : logging/slf4j dynamic dependency of logging-jetty INFO : bytebufferpool transitively enabled, ini template available with --add-modules=bytebufferpool INFO : mkdir ${jetty.base}/resources INFO : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties INFO : Base directory was modified 13 structure and its configuration.
The web applications deployed and their configurations, including the class loader information.

The prerequisite for troubleshooting is to enable JMX, so that Jetty — possibly a production server — can be accessed from a remote location to obtain the information exported via JMX, and possibly be able to reconfigure Jetty to solve the issue.

Make sure you read about how to secure the access to Jetty when using .

The Jetty Server Dump is obtained by invoking, via JMX, the

$ java -jar $JETTY_HOME/start.jar

70 operation, as shown below.

Find the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 MBean in the MBean Tree, under

$ java -jar $JETTY_HOME/start.jar

313. Then click on the "Operations" tab, select the

$ java -jar $JETTY_HOME/start.jar

314 operation, and then click the

$ java -jar $JETTY_HOME/start.jar

315 button. In the bottom panel you will see the result of the invocation, that you can copy into a text editor and save to your file system.

Taking a Jetty Server Dump is a relatively expensive operation, as it dumps the state of all connections [which can be thousands], and the state of all threads.

The result of the invocation may produce a large string, possibly few MiB, that may impact the server memory usage.

Furthermore, dumping the state of the I/O Jetty components takes a little CPU time off the handling of the actual I/O, possibly slowing it down temporarily.

While the slow-down caused by taking the Jetty Server Dump may be noticeable on highly loaded systems, it is typically a very small price to pay to obtain the information about the Jetty state that may be critical to the resolution of an issue.

The format of the Jetty Server Dump output is subject to change at any time, as Jetty developers modify the Jetty code and decide to include more state, or remove state that is no longer relevant.

The Jetty Server Dump is organized in a tree whose structure is similar to the runtime Jetty component tree.

At the end of the dump output there is a legend that explains the type of tree node: whether it is a node that represent a managed component, or an array node [or a map node] that represent some component state, etc.

The

$ java -jar $JETTY_HOME/start.jar

70 operation may also be invoked just after the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 starts [to log the state of the freshly started server], and just before the

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 stops [which may be useful to log the state of server that is not working properly].

You can temporarily enable the Jetty Server Dump at start time by overriding the

$ java -jar $JETTY_HOME/start.jar

69 property on the command line:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

To make this change persistent across server restarts, see the configuration for more information about how to configure the server to dump at start/stop time.

By default, the dump of the thread pool will only dump the topmost stack frame of each thread. It is possible to configure the thread pool to dump the whole stack trace for each thread; while this may be a little more expensive, it provides complete information about the state of each thread, which may be important to diagnose the issue.

See the configuration for more information about how to configure the thread pool to dump detailed thread information.

Detailed thread pool information can also be turned on/off on-the-fly via JMX, by finding the

$ java -jar $JETTY_HOME/start.jar

322 MBean under

$ java -jar $JETTY_HOME/start.jar

323, then selecting the

$ java -jar $JETTY_HOME/start.jar

324 attribute and setting it to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298. You can now perform the

$ java -jar $JETTY_HOME/start.jar

70 operation as explained above, and then set

$ java -jar $JETTY_HOME/start.jar

324 back to

$ java -jar $JETTY_HOME/start.jar --add-module=demos

050.

Below you can find a simple example of a Jetty Server Dump, with annotations for the principal components:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

1 The

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 instance at the root of the tree 2 The thread pool component 3 The root of the

INFO  : mkdir ${jetty.base}/start.d
INFO  : server          transitively enabled, ini template available with --add-modules=server
INFO  : logging-jetty   transitively enabled
INFO  : http            initialized in ${jetty.base}/start.d/http.ini
INFO  : resources       transitively enabled
INFO  : threadpool      transitively enabled, ini template available with --add-modules=threadpool
INFO  : logging/slf4j   dynamic dependency of logging-jetty
INFO  : bytebufferpool  transitively enabled, ini template available with --add-modules=bytebufferpool
INFO  : mkdir ${jetty.base}/resources
INFO  : copy ${jetty.home}/modules/logging/jetty/resources/jetty-logging.properties to ${jetty.base}/resources/jetty-logging.properties
INFO  : Base directory was modified

13 structure 4 The connector listening on port

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

66 for the HTTP/1.1 protocol 5 A selector component that manages connections 6 The connections currently managed by the selector component 7 The server

$ java -jar $JETTY_HOME/start.jar

332 and its classpath 8 The legend for the dump nodes

Enabling DEBUG level logging for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

277 logger name provides the maximum amount of information to troubleshoot Jetty issues.

Refer to the for more information about how to configure logging in Jetty.

Enabling DEBUG level logging for

$ java -jar $JETTY_HOME/start.jar --add-module=demos

277 is very, very expensive.

Your server could be slowed down to almost a halt, especially if it is under heavy load. Furthermore, the log file could quickly fill up the entire filesystem [unless configured to roll over], so you want to be really careful using DEBUG logging.

For production servers, consider using the first, and enable DEBUG logging only as a last resort.

However, sometimes issues are such that only DEBUG logging can really tell what’s going on in the system, and enabling DEBUG logging is your best chance to figure the issue out. Below you can find few suggestions that can help you reduce the impact when you have to enable DEBUG logging.

If Jetty instances are behind a load balancer, you may configure the load balancer to send less load to a particular Jetty instance, and enable DEBUG logging in that instance only.

In certain cases the issue can be reproduced reliably, but only in the production environment.

You can use JMX to temporarily enable DEBUG logging, reproduce the issue, and then disable DEBUG logging.

Alternatively, if you cannot reliably reproduce the issue, but you know it is happening, you can temporarily enable DEBUG logging for a small period of time, let’s say 10-60 seconds, and then disable DEBUG logging.

Changing the log level at runtime is a feature of the logging implementation that you are using.

The Jetty SLF4J implementation, used by default, exposes via JMX method

$ java -jar $JETTY_HOME/start.jar

335 that you can invoke via a JMX console to change the level for the specified logger name. The method returns

$ java -jar $JETTY_HOME/start.jar --add-module=demos

298 if the logger level was successfully changed.

For example, you can pass the string

$ java -jar $JETTY_HOME/start.jar --add-module=demos

277 as the first parameter, and the string

$ java -jar $JETTY_HOME/start.jar --add-module=demos

279 [upper case] as the second parameter. You can then use the string

$ java -jar $JETTY_HOME/start.jar --add-module=demos

280 or

$ java -jar $JETTY_HOME/start.jar --add-module=demos

281 [upper case] to restore the logging level to its previous value.

Enabling DEBUG logging for the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

277 logger name implies that all children logger names, recursively, inherit the DEBUG level.

Processing a single HTTP request involves many Jetty components: the I/O subsystem [under

$ java -jar $JETTY_HOME/start.jar

342], the thread pool [under

$ java -jar $JETTY_HOME/start.jar

343], the HTTP/1.1 parsing [under

$ java -jar $JETTY_HOME/start.jar

344], etc.

If you can cut the amount of DEBUG logging to just what you need to troubleshoot the issue, the impact of enabling DEBUG logging will be much less than enabling it for all Jetty components.

For example, if you need to troubleshoot a client that sends bad HTTP/1.1 requests, it may be enough to enable only the

$ java -jar $JETTY_HOME/start.jar

344 logger name, therefore saving the large amount of DEBUG logging produced by the I/O subsystem and by the thread pool.

In another case, you may need to troubleshoot only HTTP/2 requests, and therefore enabling only the

$ java -jar $JETTY_HOME/start.jar

346 logger name could be enough.

The Java Virtual Machines allows remote processes on different hosts to connect for debugging purposes, by using specific command line options.

While it is possible to enable remote debugging on a Jetty server, it is typically not recommended for security and performance reasons. Only enable remote debugging on a Jetty server as a last resort to troubleshoot issues that could not be troubleshot otherwise.

You can easily create a custom Jetty module [see ] with the following content:

remote-debug.mod

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

java.lang.AssertionError: Target Dir
Expected: path is directory
     but:  path does not exist

20 directive [documented ] is necessary to pass the

$ java -jar $JETTY_HOME/start.jar

348 JVM option to the forked JVM that runs Jetty, so that you can attach with a debugger.

The

$ java -jar $JETTY_HOME/start.jar --add-module=demos

785 parameter of the

$ java -jar $JETTY_HOME/start.jar

348 command line option specifies the network address and port the Jetty JVM listens on for remote debugging.

You can now enable the

$ java -jar $JETTY_HOME/start.jar

351 Jetty module with the following command issued from the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The command above minimally adds a Jetty server without connectors [via the

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

64 Jetty module] and the

$ java -jar $JETTY_HOME/start.jar

351 Jetty module, and produces the following

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

34 directory structure:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

You can easily disable the

$ java -jar $JETTY_HOME/start.jar

351 Jetty module as explained in .

Alternatively, you can enable the

$ java -jar $JETTY_HOME/start.jar

351 module on the command line, as explained in .

Starting the Jetty server with the

$ java -jar $JETTY_HOME/start.jar

351 module enabled yields:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Note how the JVM is listening on port

$ java -jar $JETTY_HOME/start.jar

359 to allow remote debuggers to connect.

If you want to avoid to fork a second JVM to pass the

$ java -jar $JETTY_HOME/start.jar

348 JVM option, please read .

The Jetty XML format is a straightforward mapping of XML elements to Java APIs so that any object can be instantiated and getters, setters, and methods can be called.

The Jetty XML format is very similar to that of frameworks like Spring or Plexus, although it predates all of them and it’s typically more powerful as it can invoke any Java API.

The Jetty XML format is used in to create the Jetty server components, as well as in to configure web applications, but it can be used to call any Java API.

The Jetty XML syntax defines XML element that allow you to call any Java API and that allow you to interact in a simpler way with the and the .

The Jetty XML elements define attributes such as

$ java -jar $JETTY_HOME/start.jar --list-modules=*

92,

$ java -jar $JETTY_HOME/start.jar

362,

$ java -jar $JETTY_HOME/start.jar

363, etc. that may be replaced by correspondent elements, so that these XML documents are equivalent:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The version using attributes is typically shorter and nicer to read, but sometimes the attribute value cannot be a literal string [for example, it could be the value of a system property] and that’s where elements gives you the required flexibility.

Element

$ java -jar $JETTY_HOME/start.jar

365 must be the root element of the XML document.

The following Jetty XML creates an empty

$ java -jar $JETTY_HOME/start.jar

366 and assigns it the id

$ java -jar $JETTY_HOME/start.jar

367:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

This is equivalent to the following Java code:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

If an object with the id

$ java -jar $JETTY_HOME/start.jar

367 already exists, then it is not created again but rather just referenced.

Within element

$ java -jar $JETTY_HOME/start.jar

364, the created object [if any] is in and may be the implicit target of other, nested, elements.

Typically the

$ java -jar $JETTY_HOME/start.jar

364 element is used to configure a

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 instance or

$ java -jar $JETTY_HOME/start.jar

372 subclasses such as

$ java -jar $JETTY_HOME/start.jar --add-module=demos

174 that represent web applications.

The following example creates a minimal Jetty

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Arguments may have a

$ java -jar $JETTY_HOME/start.jar --add-module=demos

575 attribute that explicitly performs .

Arguments may also have a

$ java -jar $JETTY_HOME/start.jar

362 attribute, which is matched with the corresponding Java annotation in the source class, that helps to identify arguments:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar --list-modules=*

90 creates a new object of the type specified by the mandatory

$ java -jar $JETTY_HOME/start.jar

363 attribute. A sequence of

$ java -jar $JETTY_HOME/start.jar

381 elements, that must be contiguous and before other elements, may be present to specify the constructor arguments.

Within element

$ java -jar $JETTY_HOME/start.jar --list-modules=*

90 the newly created object is in and may be the implicit target of other, nested, elements.

The following example creates an

$ java -jar $JETTY_HOME/start.jar

383:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

This is equivalent to the following Java code:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar

384 invokes a method specified by the mandatory

$ java -jar $JETTY_HOME/start.jar

362 attribute. A sequence of

$ java -jar $JETTY_HOME/start.jar

381 elements, that must be contiguous and before other elements, may be present to specify the method arguments.

Within element

$ java -jar $JETTY_HOME/start.jar

384 the return value, if the return type is not

$ java -jar $JETTY_HOME/start.jar

389, is in and may be the implicit target of other, nested, elements.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

This is equivalent to the following Java code:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

It is possible to call

$ java -jar $JETTY_HOME/start.jar

390 methods by specifying the

$ java -jar $JETTY_HOME/start.jar

363 attribute:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

This is equivalent to the following Java code:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

$ java -jar $JETTY_HOME/start.jar

363 attribute [or

$ java -jar $JETTY_HOME/start.jar

393 element] can also be used to specify the Java class or interface to use to lookup the non-

$ java -jar $JETTY_HOME/start.jar

390 method name. This is necessary when the object in scope, onto which the

$ java -jar $JETTY_HOME/start.jar

384 would be applied, is an instance of a class that is not visible to Jetty classes, or not accessible because it is not

$ java -jar $JETTY_HOME/start.jar

396. For example:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

In the example above,

$ java -jar $JETTY_HOME/start.jar

397 returns an object whose class is a private JDK implementation class. Without an explicit

$ java -jar $JETTY_HOME/start.jar

363 attribute [or

$ java -jar $JETTY_HOME/start.jar

393 element], it is not possible to invoke the method

$ java -jar $JETTY_HOME/start.jar

400 when it is obtained via reflection from the private JDK implementation class, because while the method is

$ java -jar $JETTY_HOME/start.jar

396, the private JDK implementation class is not, therefore this exception is thrown:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The solution is to explicitly use the

$ java -jar $JETTY_HOME/start.jar

363 attribute [or

$ java -jar $JETTY_HOME/start.jar

393 element] of the

$ java -jar $JETTY_HOME/start.jar

384 element that is invoking the

$ java -jar $JETTY_HOME/start.jar

400 method, specifying a publicly accessible class or interface that the object in scope extends or implements [in the example above

$ java -jar $JETTY_HOME/start.jar

406].

Element

$ java -jar $JETTY_HOME/start.jar

407 retrieves the value of a JavaBean property specified by the mandatory

$ java -jar $JETTY_HOME/start.jar

362 attribute.

If the JavaBean property is

$ java -jar $JETTY_HOME/start.jar

410 [or

$ java -jar $JETTY_HOME/start.jar

411],

$ java -jar $JETTY_HOME/start.jar

407 first attempts to invoke method

$ java -jar $JETTY_HOME/start.jar

413 or method

$ java -jar $JETTY_HOME/start.jar

414; failing that, attempts to retrieve the value from field

$ java -jar $JETTY_HOME/start.jar

410 [or

$ java -jar $JETTY_HOME/start.jar

411].

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

$ java -jar $JETTY_HOME/start.jar

363 attribute [or

$ java -jar $JETTY_HOME/start.jar

393 element] allows to perform

$ java -jar $JETTY_HOME/start.jar

390 calls, or to lookup the getter method from the specified class, as described in the .

Element

$ java -jar $JETTY_HOME/start.jar

421 stores the value of a JavaBean property specified by the mandatory

$ java -jar $JETTY_HOME/start.jar

362 attribute.

If the JavaBean property is

$ java -jar $JETTY_HOME/start.jar

410 [or

$ java -jar $JETTY_HOME/start.jar

411],

$ java -jar $JETTY_HOME/start.jar

421 first attempts to invoke method

$ java -jar $JETTY_HOME/start.jar

427 with the value in the as argument; failing that, attempts to store the value in the scope to field

$ java -jar $JETTY_HOME/start.jar

410 [or

$ java -jar $JETTY_HOME/start.jar

411].

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

$ java -jar $JETTY_HOME/start.jar

363 attribute [or

$ java -jar $JETTY_HOME/start.jar

393 element] allows to perform

$ java -jar $JETTY_HOME/start.jar

390 calls, or to lookup the setter method from the specified class, as described in the .

Element

$ java -jar $JETTY_HOME/start.jar

434 allows the creation of a new

$ java -jar $JETTY_HOME/start.jar

437 implementation, specified by the

$ java -jar $JETTY_HOME/start.jar

363 attribute — by default a

$ java -jar $JETTY_HOME/start.jar

439.

The map entries are specified with a sequence of

$ java -jar $JETTY_HOME/start.jar

435 elements, each with exactly 2

$ java -jar $JETTY_HOME/start.jar

441 elements, for example:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar

442 is a convenience element that puts a key/value pair into objects that implement

$ java -jar $JETTY_HOME/start.jar

437. You can only specify the key value via the

$ java -jar $JETTY_HOME/start.jar

362 attribute, so the key can only be a literal string [for keys that are not literal strings, use the

$ java -jar $JETTY_HOME/start.jar

384 element].

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar

447 creates a new array, whose component type may be specified by the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

575 attribute, or by a

$ java -jar $JETTY_HOME/start.jar

451 child element.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar

452 allows you to reference an object via the

$ java -jar $JETTY_HOME/start.jar

454 attribute`, putting it into so that nested elements can operate on it. You must give a unique

$ java -jar $JETTY_HOME/start.jar --list-modules=*

92 attribute to the objects you want to reference.

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar --add-modules=http

00 retrieves the value of the Jetty module property specified by the

$ java -jar $JETTY_HOME/start.jar

362 attribute, and it is mostly used when creating or when using .

The

$ java -jar $JETTY_HOME/start.jar

459 attribute allows you to specify a comma separated list of old, deprecated, property names for backward compatibility.

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

06 attribute allows you to specify a default value for the property, if it has not been explicitly defined.

For example, you may want to configure the context path of your web application in this way:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

The

$ java -jar $JETTY_HOME/start.jar

14 value is resolved by looking for the Jetty module property

$ java -jar $JETTY_HOME/start.jar

462; if this property is not set, then the default value of

$ java -jar $JETTY_HOME/start.jar

463 is used.

Element

$ java -jar $JETTY_HOME/start.jar

464 retrieves the value of the JVM system property specified by the

$ java -jar $JETTY_HOME/start.jar

362 attribute, via

$ java -jar $JETTY_HOME/start.jar

467.

The

$ java -jar $JETTY_HOME/start.jar

459 attribute allows you to specify a comma separated list of old, deprecated, system property names for backward compatibility.

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

06 attribute allows you to specify a default value for the system property value, if it has not been explicitly defined.

The following example creates a minimal Jetty

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 that listens on a port specified by the

$ java -jar $JETTY_HOME/start.jar

471 system property:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Element

$ java -jar $JETTY_HOME/start.jar

472 retrieves the value of the environment variable specified by the

$ java -jar $JETTY_HOME/start.jar

362 attribute, via

$ java -jar $JETTY_HOME/start.jar

475.

The

$ java -jar $JETTY_HOME/start.jar

459 attribute allows you to specify a comma separated list of old, deprecated, environment variable names for backward compatibility.

The

$ java -jar $JETTY_HOME/start.jar --add-modules=http

06 attribute allows you to specify a default value for the environment variable value, if it has not been explicitly defined.

The following example creates a minimal Jetty

$ java -jar $JETTY_HOME/start.jar --list-modules=*

42 that listens on a port specified by the

$ java -jar $JETTY_HOME/start.jar

479 environment variable:

$ JETTY_BASE=/path/to/jetty.base $ mkdir $JETTY_BASE $ cd $JETTY_BASE

Elements that have the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

575 attribute explicitly perform the type coercion of the string value present in the XML document to the Java type specified by the

$ java -jar $JETTY_HOME/start.jar --add-module=demos

575 attribute.

Supported types are the following:

all primitive types and their boxed equivalents, for example $ java -jar $JETTY_HOME/start.jar 482 but also $ java -jar $JETTY_HOME/start.jar 483 [short form] and $ java -jar $JETTY_HOME/start.jar 484 [fully qualified form]
$ java -jar $JETTY_HOME/start.jar 485, in both short form and fully qualified form
$ java -jar $JETTY_HOME/start.jar 486, in both short form and fully qualified form
$ java -jar $JETTY_HOME/start.jar 487, in both short form and fully qualified form

Elements that create new objects or that return a value create a scope. Within these elements there may be nested elements that will operate on that scope, i.e. on the new object or returned value.

1.

1 certificate; this certificate may be signed by Certificate Authority

2.

2 certificate; this certificate may be signed by Certificate Authority

3; and so on until the Root Certificate Authority.

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