I'm working on a project powered by Payara Micro and it is configured by a domain.xml file.

I'm facing an issue with the @Asynchronous annotation.

While the Oracle documentation explains this:

Clients calling asynchronous methods, however, immediately have control returned to them by the enterprise bean container.

https://docs.oracle.com/javaee/7/tutorial/ejb-async001.htm

My @Asynchronous annotated method does not return immediately.

@Path("foo")
public class FooResource {
  @GET
  public String get() {
    System.out.println("Request started");
    this.doSomething();
    System.out.println("Request ended");
    return "Hello world! ";
  }

  @Asynchronous
  public void doSomething() {
    try {
      System.out.println("Long task started");
      Thread.sleep(2000);
      System.out.println("Long task ended");
    } catch (InterruptedException e) {
      System.out.println("Long task failed");
    }
  }
}

In my mind it should result in:

Request started
Long task started
Request ended
Long task ended

but it results in:

Request started
Long task started
Long task ended
Request ended

I published on Github a simple Gradle project to reproduce the behavior here.

CodePudding user response：

Your method invocation will be truly asynchronous if you actually invoke the method of an EJB. The call in your sample is a local method call, completely bypassing the container and its annotation processing.

A proper EJB invocation would require an actual EJB:

@Stateless
class MyEJB {

  @Asynchronous
  public void doSomething() {
    try {
      System.out.println("Long task started");
      Thread.sleep(2000);
      System.out.println("Long task ended");
    } catch (InterruptedException e) {
      System.out.println("Long task failed");
    }
  }
}

... and the method invocation in your resource class:

class MyResource {

@Inject MyEJB myEJB;

@Path("foo")
public class FooResource {
  @GET
  public String get() {
    System.out.println("Request started");
    myEJB.doSomething(); // <-- This is the important change!
    System.out.println("Request ended");
    return "Hello world! ";
  }
}