wasmtime-java

Java (or any JVM) language binding for Wasmtime.

Some basic examples are working, but many API implementations are work in progress.

Declaring Dependencies

Gradle example:

repositories {
    mavenCentral()
}

dependencies {
    implementation "io.github.kawamuray.wasmtime:wasmtime-java:$LATEST_VERSION"
}

An artifact (JAR) of wasmtime-java ships along with prebuilt JNI libraries for some major platforms, so just adding the above dependency provides you a self-contained wasmtime runtime on supported platforms:

Example

See examples for the full example.

public class HelloWasm {
    public static void main(String[] args) {
        try (Store<Void> store = Store.withoutData();
             Engine engine = store.engine();
             Module module = Module.fromFile(engine, "./hello.wat");
             Func helloFunc = WasmFunctions.wrap(store, () -> {
                 System.err.println(">>> Calling back...");
                 System.err.println(">>> Hello World!");
             })) {
            Collection<Extern> imports = Arrays.asList(Extern.fromFunc(helloFunc));
            try (Instance instance = new Instance(store, module, imports)) {
                try (Func f = instance.getFunc("run").get()) {
                    WasmFunctions.Consumer0 fn = WasmFunctions.consumer(f);
                    fn.accept();
                }
            }
        }
    }
}

Run example:

$ ./gradlew -Pmain=examples.HelloWorld examples:run

How to build

$ ./gradlew build

License

Apache License Version 2.0