Simple Asynchronous methods in EJB 3.1

EJB 3.1 introduced a simple mechanism for asynchronous invocation. This post presents such an example with a Singleton session bean and its JUnit test case. 2 styles of asynchronous EJB invocations are used:

(1) fire-and-forget asynchronous methods having void return type.

(2) retrieve-result-later asynchronous methods having Future return type.
package test;

import java.util.concurrent.Future;
import javax.ejb.Asynchronous;
import javax.ejb.AsyncResult;
import javax.ejb.Singleton;

public class AsyncBean {
    @Asynchronous  //this line can be omitted
    public void ignoreResult(int a, int b) {
        // the client doesn't care what happens here

    @Asynchronous  //this line can be omitted
    public Future longProcessing(int a, int b) {
        return new AsyncResult(a * b);
Since the class is annotated with @Asynchronous, all business methods are asynchronous.  The method-level @Asynchronous is therefore redundant, and kept there for illustration purpose.package test;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import javax.ejb.embeddable.EJBContainer;
import javax.naming.Context;
import junit.framework.TestCase;

public class AsyncBeanTest extends TestCase {
    private EJBContainer container;
    private Context namingContext;
    private AsyncBean asyncBean;

    protected void setUp() throws Exception {
        container = EJBContainer.createEJBContainer();
        namingContext = container.getContext();
        asyncBean = (AsyncBean) namingContext.lookup("java:global/testApp/AsyncBean");

    protected void tearDown() throws Exception {

    public final void testIgnoreResult() {
        asyncBean.ignoreResult(0, 0); // fire and forget
        System.out.println("Proceed without waiting for the async method result.");

    public final void testLongProcessing() throws InterruptedException, ExecutionException {
        Future futureResult = asyncBean.longProcessing(8, 9);
        System.out.println("Proceed to other tasks and check async method result later.");
        Integer intResult = futureResult.get();
        System.out.println("The prior async method returned " + intResult);

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