This documentation is for an old GraalVM version. See the latest version.

Build Java Modules into a Native Executable

GraalVM Native Image supports the Java Platform Module System, introduced in Java 9, which means you can convert a modularized Java application into a native executable.

The native-image tool accepts the module-related arguments like --module (-m), --module-path (-p), --add-opens, --add-exports (same as for the java launcher). When such a module-related argument is used, the native-image tool itself is used as a module too.

In addition to supporting --add-reads and --add-modules, all module related options are considered prior to scanning the modulepath. This helps prevent class loading errors and allow for better module introspection at run time.

The command to build a native executable from a Java module is:

native-image [options] --module <module>[/<mainclass>] [options]

Run a Demo #

Follow the steps below to practice building a modular Java application into a native executable. For the demo, you will use a simple HelloWorld Java module gathered with Maven:

├── hello
│   └── Main.java
│       > package hello;
│       > 
│       > public class Main {
│       >     public static void main(String[] args) {
│       >         System.out.println("Hello from Java Module: "
│       >             + Main.class.getModule().getName());
│       >     }
│       > }
│
└── module-info.java
    > module HelloModule {
    >     exports hello;
    > }

Download or clone the demos repository and navigate to the directory native-hello-module:
```
 git clone https://github.com/graalvm/graalvm-demos
 cd native-hello-module
```
Compile and package the project with Maven:
```
 mvn package
```

Test running it on GraalVM’s JDK:

 $JAVA_HOME/bin/java --module-path target/HelloModule-1.0-SNAPSHOT.jar --module HelloModule

Now build this module into a native executable:
```
 $JAVA_HOME/bin/native-image --module-path target/HelloModule-1.0-SNAPSHOT.jar --module HelloModule
```
It builds the modular Java application into a native executable called hellomodule in the project root directory that you can execute:
```
 ./hellomodule
```

Learn more how you can access resources for a Java module at run time.

Build Java Modules into a Native Executable

Run a Demo #

Related Documentation #

Connect with us