Packaging Overview

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.

Topics:

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 a dmg

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.