JAXRS Asynchronous Services

Question

Here's a sample code from Jersey docs for Asynchronous Services:

@Path("/resource")
public class AsyncResource {
    @GET
    public void asyncGet(@Suspended final AsyncResponse asyncResponse) {

        new Thread(new Runnable() {
            @Override
            public void run() {
                String result = veryExpensiveOperation();
                asyncResponse.resume(result);
            }

            private String veryExpensiveOperation() {
                // ... very expensive operation
            }
        }).start();
    }
}

Considering that container is already in charge of releasing the connection handling thread back to the pool and handing the request processing to a worker thread, I'm wondering why we still need to spawn a new thread programmatically? Shouldn't this be just a matter of container configuration (setting number of worker threads)?

simdevmon simdevmon · Accepted Answer · 2017-03-29T14:09:28

There is no need to spwan a new thread like this. If you are in an JavaEE environment you can simply place an @Asynchronous annotation to your method:

@GET
@Asynchronous
public void asyncGet(@Suspended final AsyncResponse asyncResponse) {
        String result = veryExpensiveOperation();
        asyncResponse.resume(result);
}

I you need extended thread pooling you can also have a look at ManagedExecutorService.

JAXRS Asynchronous Services

2 Answers