GraalVM Native Image Plugin

---

This plugin offers a task (nativeImage), which wraps GraalVM's tool native-image installed in a machine.

Configuration

NativeImageTask

You can configure options via nativeImage {}.

• graalVmHome - The Home directory of GraalVM, required.
• jarTask - A task of JarTask whose output jar will be converted to native executable.(default: jar task)
• mainClass - (Deprecated, configure via buildType { executable { main = ... } }) A name of main class, required.
• executableName - A name of executable, required.
• runtimeClasspath - A configuration of runtime classpath.(default: runtimeClasspath Configuration)
• outputDirectory - An output directory under which the native image will be generated.(default: $buildDir/native-image)
• buildType {} - A type of build, required. BuildTypeSelector will be passed to this closure.
  • buildTypeSelector.sharedLibrary - To build shared library, return this.
  • buildTypeSelector.executable {} - To build executable, call executable {} block, and configure its main with the application's main class name.

You can configure arguments to be passed to GraalVM via arguments(String...) method.

• arguments(String...) - native-image command's arguments.
• arguments(Provider<String>...) - native-image command's arguments with Provider<String> type.
• arguments {} - Configure native-image command's arguments in configuration block.
  • add(String) - Equivalent to arguments(String...).
  • add(Provider<String>) - Equivalent to arguments(Provider<String>...).

For more information, please see appendix at the bottom of this README.

GenerateNativeImageConfigTask

You can configure running application parameters by generateNativeImageConfig {} block(GenerateNativeImageConfigTask).

• enabled - A boolean property whether to run this task. This plugin disables generateNativeImageConfig task in default. Please set true to this property to run generateNativeImageConfig task.
• mainClass - The main class name for running application.
• byRunningApplication {} - Configuration block to run your application. You can configure multiple times.
  • stdIn(String) - standard input for your application.
  • arguments(String...) - Command line arguments, which will be given to your application.
  • environment(Map<String, String>) - Environmental variable for your application.
• byRunningApplicationWithoutArguments() - Run application without any configuration.

Example

1. Example script of building executable.

Gradle Groovy DSL

plugins {
  id 'java'
  id 'org.mikeneck.graalvm-native-image' version 'v1.4.0'
}

repositories {
  mavenCentral()
}

dependencies {
  implementation 'org.slf4j:slf4j-simple:1.7.28'
}

import org.mikeneck.graalvm.BuildTypeSelector

nativeImage {
  graalVmHome = System.getProperty('java.home')
  mainClass = 'com.example.App' // Deprecated, use buildType.executable.main as follows instead.
  buildType { BuildTypeSelector build ->
    build.executable {
      main = 'com.example.App'
    }
  }
  executableName = 'my-native-application'
  outputDirectory = file("$buildDir/bin")
  arguments {
    add '--no-fallback'
    add '--enable-all-security-services'
    add options.traceClassInitialization('com.example.MyDataProvider,com.example.MyDataConsumer')
    add '--initialize-at-run-time=com.example.runtime'
    add '--report-unsupported-elements-at-runtime'
  }
}

generateNativeImageConfig {
  enabled = true
  byRunningApplication {
    stdIn("""
    |total: 2
    |contents:
    |  - name: foo
    |    size: 2052
    |""".stripMargin())
  }
  byRunningApplicationWithoutArguments()
  byRunningApplication {
    arguments('-h')
  }
}

Gradle Kotlin DSL

import org.mikeneck.graalvm.GenerateNativeImageConfigTask

plugins {
  kotlin("jvm") version "1.3.72"
  id("org.mikeneck.graalvm-native-image") version "v1.4.0"
}

repositories {
  mavenCentral()
}

dependencies {
  implementation("org.slf4j:slf4j-simple:1.7.28")
}

nativeImage {
    graalVmHome = System.getenv("JAVA_HOME")
    mainClass ="com.example.App" // Deprecated, use `buildType.executable.main` as follows instead.
    buildType { build ->
      build.executable(main = 'com.example.App')
    }
    executableName = "my-native-application"
    outputDirectory = file("$buildDir/executable")
    arguments(
        "--no-fallback",
        "--enable-all-security-services",
        options.traceClassInitialization('com.example.MyDataProvider,com.example.MyDataConsumer'),
        "--initialize-at-run-time=com.example.runtime",
        "--report-unsupported-elements-at-runtime"
    )
}

generateNativeImageConfig {
  enabled = true
  byRunningApplication {
    stdIn("""
      |total: 2
      |contents:
      |  - name: foo
      |    size: 2052
      |""".trimMargin())
  }
  byRunningApplicationWithoutArguments()
  byRunningApplication {
    arguments('-h')
  }
}

2. Example script of building shared library.

Shared library feature is one of GraalVM's feature to build shared library('so' file in linux, 'dylib' file in OS X), only available Java11 or later.

Gradle Groovy DSL

plugins {
  id 'java'
  id 'org.mikeneck.graalvm-native-image' version 'v1.4.0'
}

repositories {
  mavenCentral()
}

dependencies {
  implementation 'org.slf4j:slf4j-simple:1.7.28'
}

import org.mikeneck.graalvm.BuildTypeSelector

nativeImage {
  graalVmHome = System.getProperty('java.home')
  buildType { BuildTypeSelector build ->
    build.sharedLibrary
  }
  executableName = 'my-native-lib'
  outputDirectory = file("$buildDir/native-lib")
  arguments {
    add '--no-fallback'
    add '--enable-all-security-services'
    add options.traceClassInitialization('com.example.MyDataProvider,com.example.MyDataConsumer')
    add '--initialize-at-run-time=com.example.runtime'
    add '--report-unsupported-elements-at-runtime'
  }
}

generateNativeImageConfig {
  enabled = true
  // If config file generation is required, set main class name here in generateNativeImageConfig block.
  mainClass = 'com.example.RunMainForGenerateConfigJson'
  byRunningApplication {
    stdIn("""
    |total: 2
    |contents:
    |  - name: foo
    |    size: 2052
    |""".stripMargin())
  }
  byRunningApplicationWithoutArguments()
  byRunningApplication {
    arguments('-h')
  }
}

Gradle Kotlin DSL

import org.mikeneck.graalvm.GenerateNativeImageConfigTask

plugins {
  kotlin("jvm") version "1.3.72"
  id("org.mikeneck.graalvm-native-image") version "v1.4.0"
}

repositories {
  mavenCentral()
}

dependencies {
  implementation("org.slf4j:slf4j-simple:1.7.28")
}

nativeImage {
    graalVmHome = System.getenv("JAVA_HOME")
    buildType { sharedLibrary }
    executableName = "my-native-lib"
    outputDirectory = file("$buildDir/native-lib")
    arguments(
        "--no-fallback",
        "--enable-all-security-services",
        options.traceClassInitialization('com.example.MyDataProvider,com.example.MyDataConsumer'),
        "--initialize-at-run-time=com.example.runtime",
        "--report-unsupported-elements-at-runtime"
    )
}

generateNativeImageConfig {
  enabled = true
  // If config file generation is required, set main class name here in generateNativeImageConfig block.
  mainClass = "com.example.RunMainForGenerateConfigJson"
  byRunningApplication {
    stdIn("""
      |total: 2
      |contents:
      |  - name: foo
      |    size: 2052
      |""".trimMargin())
  }
  byRunningApplicationWithoutArguments()
  byRunningApplication {
    arguments('-h')
  }
}

run task

For linux/mac users

(Optional)Before running nativeImage task, GraalVM and native-image command should be installed. Version v0.5.0 or later, the plugin has installNativeImage task which execute installation command(gu install native-image) so that users do not need to run gu command.

# Prerequisites: GraalVM is installed to your machine.
# Then install native-image.
$ gu install native-image

# Run nativeImage task.
$ ./gradlew nativeImage

# An executable will be created at native-image directory under the project's build directory
$ ls build/native-image
my-native-application

For Windows users

Make sure you are running nativeImage task on Windows SDK 7.1 Command Prompt.

For GitHub Actions

If you are planning releasing both MacOS X and Linux applications, please refer example workflow under example directory.

generateNativeImageConfig task

This task requires native-image command. If your machine has no native-image command, run gu command or installNativeImage task before running generateNativeImageConfig task.

---

nativeImage task configuration appendix

TraceClassInitialization option

As of GraalVM 20.3.0, the way to pass TraceClassInitialization option is changed. So we offer a convenient way to create TraceClassInitialization option. In this way you can create the option via an options object available from nativeImageTask.

nativeImage {
  arguments {
    // When used with GraalVM 20.3.0 or later
    // -H:TraceClassInitialization=com.example.WantTracingInInitializationClass,com.example.Another
    // When used with GraalVM 20.2.0 or earlier
    // -H:+TraceClassInitialization
    add options.traceClassInitialization { 'com.example.WantTracingInInitializationClass,com.example.Another' }
  }
}