Using groovy.lang.Closure in Java application

Question

I would like to use the Groovy Closure class in a Java application, but am having more trouble than expected. Here's what I have:

int count = 0;
groovy.lang.Closure closure = { count = 1 };

However, when I try to compile this using JDK 7, I get the error: illegal initializer for Closure

Am I missing something really obvious? Thanks for your help.

Answer 1

There's already an answer above, I am simply adding an working example.

Groovy Code that accepts closure,

public class GroovyService {

    Integer doSomething(Closure<Integer> fn) {
        fn()
    }
}

Calling groovy closure From java,

import groovy.lang.Closure;

public class JavaCanCallGroovy {

    public static void main(String[] args) {

        GroovyService service = new GroovyService();

        Integer data = service.doSomething(new Closure<Integer>(null) { //need to pass owner = null
            @Override
            public Integer call() {
                return 100;
            }
        });

        System.out.println(data);
    }
}

Call groovy closure from scala

import groovy.lang.Closure

object ScalaCanCallGroovy extends App {

  private val closure = new Closure[Integer]() {
    override def call() = 1
  }

  val groovyService = new GroovyService
  val data = groovyService.doSomething(closure)

  assert(data == 1)
}