Link

Since Apache Ant 1.10.6

Description

Assembles jmod files into an executable image. Equivalent to the JDK's jlink tool.

Requires Java 9 or later.

Parameters

Parameters specified as nested elements

<link> can have the following nested elements:

• modulepath
• module
• observableModule
• launcher
• locale
• resourceOrder
• excludeResources
• excludeFiles
• compress
• releaseInfo

modulepath

Path-like structure pointing to jmod files to link into image.

module

Names a single module to be placed in the linked image. This may be specified multiple times.

Attributes:

observableModule

Names a module visible to the linking process, instead of every module in the module path being considered. This may be specified multiple times.

Attributes:

launcher

Specifies an executable file which will be added to the linked image, which executes a particular module's main class. Attributes:

locale

Specifies locales to include in linked image. May be specified multiple times. Requires jdk.localedata module. Attributes:

Attribute	Description	Required
name	Name of locale, or wildcard pattern with * that matches multiple locale names.	Yes

resourceOrder

Explicit resource search order in linked image. May be specified multiple times. Attributes:

If the resourceOrder attribute is also present on the task, its patterns are treated as if they occur before patterns in nested elements.

excludeResources

Excludes files from linked image tree. May be specified multiple times. Attributes:

excludeFiles

Excludes files from linked image. May be specified multiple times. Attributes:

compress

Describes how image should be compressed. Attributes:

<compress> can also have any number of nested <files> elements, with these attributes:

releaseInfo

Replaces, augments, or trims the image's release info properties. Can be specified multiple times. Attributes:

Attribute	Description	Required
file	Java properties file containing new release info properties that will entirely replace the current ones.	No
delete	Comma-separated property keys to remove from application's release info	No

<releaseInfo> can also have any number of these nested elements:

add

Specifies additional release info properties. Attributes:

delete

Property keys to remove from applicaiton's release info. Attributes:

Examples

Basic linking

<jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/>
<link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp"/>

Custom binaries

This will cause a bin/MyEditor script to appear in the image:

<jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/>
<link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp"
      launchers="MyEditor=com.example.myapp/com.example.myapp.editors.EditorMain"/>

Same thing, using a nested launcher element:

<jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/>
<link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp">

    <launcher name="MyEditor" module="com.example.myapp"
              mainClass="com.example.myapp.editors.EditorMain"/>

</link>

Limiting locales

Include just the locales needed by the application from the jdk.localedata module:

<jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/>
<link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp,jdk.localedata"
      locales="zh,jp-*"/>

Compressed image

Compress entire image:

<jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/>
<link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp,jdk.localedata"
      compress="zip"/>

Compress only some files in the image:

<jmod destfile="MyApp.jmod" classpath="build/myapp.jar"/>
<link destDir="build/image" modulepath="MyApp.jmod"
      modules="com.example.myapp,jdk.localedata">

    <compress level="zip" files=".*\.xml"/>

</link>

Cross-compiling

To create an image for a different platform:

• Download the JDK for that platform, and expand the archive manually into a directory of your choice. (Downloading a zip or tar.gz version of a JDK instead of an installer will make this easier.)
• Determine the foreign JDK's platform string. This can be done with a command that examines the JDK's jmods/java.base.jmod file:

  jmod describe "$FOREIGN_JDK_HOME"/jmods/java.base.jmod | grep '^platform'
  

• Create your jmod using the foreign JDK's platform string:

  <jmod destfile="MyApp.jmod" classpath="build/myapp.jar" platform="windows-amd64"/>
  

• Link with the foreign JDK's jmods directory in the module path:

  <link destDir="build/image"
        modulepath="MyApp.jmod;${foreign-jdk-home}/jmods"
        modules="com.example.myapp"/>