1 Packaging Overview
The packaging tool jpackage
enables you to generate installable packages for modular and non-modular Java applications. Platform-specific packages for Linux, macOS and Windows provide your users with a familiar way to install and launch your applications.
The simplest form of packaging takes a pre-built Java application as input and generates an installable package in a platform-dependent default format. The packaging tool generates a runtime for your application using the jlink
command.
For applications that require more advanced capabilities, command line options are available for features such as the following:
- Provide a custom icon
- Install the application in a specific location
- Specify JVM options and application arguments to be used when launching the application
- Set file associations to launch the application when an associated file type is opened
- Launch the application from a platform-specific menu group
- Set up multiple launchers for the application
- Sign the bundle (macOS only)
For a description of jpackage
and its options, see The jpackage Command in Java Development Kit Tool Specifications.
Packaging Pre-Reqs
Application packages must be built on the target platform. The system used for packaging must contain the application, a JDK, and software needed by the packaging tool.
To package your application for multiple platforms, you must run the packaging tool on each platform. If you want more than one format for a platform, you must run the tool once for each format.
The following platforms and formats are supported with the required software:
-
Linux:
deb
,rpm
:-
For Red Hat Linux, the rpm-build package is required.
-
For Ubuntu Linux, the fakeroot package is required.
-
-
macOS:
pkg
,app
in admg
Xcode command line tools are required when the
--mac-sign
option is used to request that the package be signed, and when the--icon
option is used to customize the DMG image. -
Windows:
exe
,msi
WiX 3.0 or later is required.
Application Preparation
To package your application, you must first build it and create the necessary JAR or module files. Resources needed by your application must also be available on the system used for packaging.
The following application-related information and resources are used for packaging:
- JAR or module files for the application
- Application metadata, for example, name, version, description, copyright, license file
- Installation options, for example, shortcut, menu group, additional launchers, file associations
- Launch options, for example, application arguments, JVM options
As part of the packaging process, an application image based on the files in the input directory is created. This image is described in Generated Application Image. To test your application before creating an installable package, use the --type app-image
option to create only the application image.
Generated Application Image
The packaging tool creates an application image based on the input to the tool.
The following example shows the application image created for a simple Hello World application for each platform. Files that are considered implementation details are subject to change and are not shown.
-
Linux:
myapp/ bin/ // Application launchers HelloWorld lib/ app/ HelloWorld.cfg // Configuration info, created by jpackage HelloWorld.jar // JAR file, copied from the --input directory runtime/ // Java runtime image
-
macOS:
HelloWorld.app/ Contents/ Info.plist MacOS/ // Application launchers HelloWorld Resources/ // Icons, etc. app/ HelloWorld.cfg // Configuration info, created by jpackage HelloWorld.jar // JAR file, copied from the --input directory runtime/ // Java runtime image
-
Windows:
HelloWorld/ HelloWorld.exe // Application launchers app/ HelloWorld.cfg // Configuration info, created by jpackage HelloWorld.jar // JAR file, copied from the --input directory runtime/ // Java runtime image
The application image generated by the tool works for most applications. However, you can make changes before packaging the image for distribution, if needed.
Java Runtime Requirements
To eliminate the need for users to install a Java runtime, one is packaged with your applications. The packaging tool generates a runtime image based on the packages or modules that your application needs.
If no Java runtime image is passed to the packaging tool, then
jpackage
uses the jlink
tool to create a runtime
for the application. Runtime images created by the packaging tool do not contain debug
symbols, the usual JDK commands, man pages, or the src.zip
file.
-
For non-modular applications composed of JAR files, the generated runtime image contains the same set of JDK modules that is provided to class-path applications in the unnamed module by the regular
java
launcher. It doesn't include the available service providers, but you can add them with the--jlink-options
option and passing it the--bind-services
jlink
option:jpackage --name DynamicTreeDemo \ --input . --main-jar DynamicTreeDemo.jar \ --jlink-options --bind-services
To add additional modules, use the
--add-modules
option:jpackage --name DynamicTreeDemo \ --input . --main-jar DynamicTreeDemo.jar \ --module-path $JAVA_HOME/jmods \ --add-modules java.logging
-
For modular applications composed of modular JAR files and JMOD files, the generated runtime image contains the application's main module and the transitive closure of all of its dependencies. It doesn't include the available service providers, but you can add them with the
--jlink-options
option and passing it the--bind-services
jlink
option:jpackage --name Hello --module-path mods \ --module com.greetings/com.greetings.Main \ --jlink-options --bind-services
To add additional modules, use the
--add-modules
option:jpackage --name Hello --module-path "mods:$JAVA_HOME/jmods" \ --add-modules java.logging \ --module com.greetings/com.greetings.Main
Note:
If you don't specify the--jlink-options
option, then, by default,
the jpackager
tool adds these jlink
options:
--strip-native-commands
, --strip-debug
,
--no-man-pages
, and --no-header-files
.
The runtime image generated by the tool works for most applications. However, you can create a custom runtime to package with your application, if needed.