Overview

This plugin provides integration with the jlink tool. The plugin requires Gradle to be run with JDK 11+. The minimally supported Gradle version is 6.8.

Your application has to be fully modularized in order to be used with this plugin. The plugin does not do any nasty tricks to fool jlink into working with non-modularized applications.

If you have third party dependencies that are not modularized, you should consider using extra-java-module-info plugin in order to elegantly add the module-info.class descriptors to those libraries.

The examples below assume the Gradle version is 8.4 or higher and are written in Groovy DSL.

When applied together with java plugin, the plugin contributes the image, imageRun, and imageModules tasks to the project.

The image that is built by the image task is meant to be used for development purposes only as it depends on the local JDK.

If you want to distribute your application, please refer to the "Cross Target Images" section of this document.

Usage

With application plugin

If used together with application plugin, the plugin will infer the mainModule, mainClass, applicationDefaultJvmArgs, and applicationName configuration properties from the application extension.

plugins {
    id 'application'
    id 'com.github.iherasymenko.jlink' version '0.6'
}

application {
    mainClass = 'com.example.demo.DemoApplication'
    mainModule = 'demo.main'
}

With java plugin

plugins {
    id 'java'
    id 'com.github.iherasymenko.jlink' version '0.6'
}

jlinkApplication {
    mainClass = 'com.example.demo.DemoApplication'
    mainModule = 'demo.main'
}

Optional configuration

jlinkApplication {
    addOptions = ['-Xmx8G', '-Xms8G']
    compress = 'zip-9'
    noHeaderFiles = true
    noManPages = true
    stripDebug = true
    generateCdsArchive = true
    dedupLegalNoticesErrorIfNotSameContent = true
    disablePlugin = [
        "add-options"
    ]
    excludeFiles = ['/**/legal/**', '/**/man/**']
    excludeResources = ['/**/com/example/demo/DemoApplication.class']
    includeLocales = ['en-CA']
    stripJavaDebugAttributes = true
    stripNativeCommands = true
    addModules = ['java.net.http']
    launcher = [
        'another-demo-application': 'demo.main/com.example.demo.AnotherDemoApplication'
    ]
    limitModules = ['com.zaxxer.hikari']
    vm = 'server'
    endian = 'little'
    vendorVersion = 'My JRE version 99.9'
    vendorBugUrl = 'https://github.com/iherasymenko/jlink-gradle-plugin/issues?q=label:bug'
    vendorVmBugUrl = 'https://github.com/iherasymenko/jlink-gradle-plugin/issues?q=label:vmbug'
}

Cross Target Images

The plugin supports building images for multiple platforms. If you want to distribute your application, you have to be explicit about the JDK you want to use as the base image. jlink supports building cross-platform images, but it requires the JDK to be of the same major version as jlink.

The plugin provides the jlinkImages extension that allows you to specify the JDKs you want to use for building the images.

The JDKs will be fetched from a repository (CDN) that you have to configure.

Below is an example of how to configure the plugin to use Azul Zulu OpenJDK public CDN as the repository.

build.gradle

plugins {
    id 'application'
    id 'com.github.iherasymenko.jlink' version '0.6'
}

application {
    mainClass = 'com.example.demo.DemoApplication'
    mainModule = 'demo.main'
}

jlinkImages {
	linuxX64 {
		group = 'com.azul.cdn'
		jdkArchive = 'zulu21.30.15-ca-jdk21.0.1-linux_x64.zip'
	}
	windowsX64 {
		group = 'com.azul.cdn'
		jdkArchive = 'zulu21.30.15-ca-jdk21.0.1-win_x64.zip'
	}
	macOsX64 {
		group = 'com.azul.cdn'
		jdkArchive = 'zulu21.30.15-ca-jdk21.0.1-macosx_x64.tar.gz'
	}
}

settings.gradle

dependencyResolutionManagement {
    repositories {
        ivy {
            url = uri('https://cdn.azul.com/zulu/bin/')
            patternLayout {
                artifact '[artifact].[ext]'
            }
            metadataSources {
                artifact()
            }
            content {
                includeGroup 'com.azul.cdn'
            }
        }
    }
}

The above configuration will create three tasks: imageLinuxX64, imageWindowsX64, and imageMacOsX64 accordingly. These tasks will be attached to the assemble task as dependencies.

Or you can use the Eclipse Temurin™ OpenJDK GitHub releases as the repository:

build.gradle

jlinkImages {
    linuxX64 {
        group = 'net.adoptium.cdn'
        jdkArchive = 'OpenJDK21U-jdk_x64_linux_hotspot_21.0.1_12.tar.gz'
    }
}

settings.gradle

dependencyResolutionManagement {
    repositories {
        ivy {
            url = uri('https://github.com/adoptium/temurin21-binaries/releases/download/jdk-21.0.1%2B12/')
            patternLayout {
                artifact '[artifact].[ext]'
            }
            metadataSources {
                artifact()
            }
            content {
                includeGroup 'net.adoptium.cdn'
            }
        }
    }
}

Or you can even tell the plugin to use GitHub releases of IBM Semeru OpenJDK as the repository:

build.gradle

jlinkImages {
	linuxX64Semuru {
		group = 'com.ibm.semuru.cdn'
		jdkArchive = 'ibm-semeru-open-jdk_x64_linux_17.0.8.1_1_openj9-0.40.0.tar.gz'
	}
}

settings.gradle

dependencyResolutionManagement {
    repositories {
        ivy {
            url = uri('https://github.com/ibmruntimes/semeru17-binaries/releases/download/jdk-17.0.8.1%2B1_openj9-0.40.0/')
            patternLayout {
                artifact '[artifact].[ext]'
            }
            metadataSources {
                artifact()
            }
            content {
                includeGroup 'com.ibm.semuru.cdn'
            }
        }
    }
}

Because this plugin delegates downloading of the JDKs to Gradle, the JDK archives will be included in the Dependency Verification if your project has this feature enabled.