get() immediately after obtaining ListenableFuture

Question

If I get a ListenableFuture<X> when calling an external system using the AsyncHttpClient, and I call get() immediately - will the current thread not wait until the async thread is ready with a Response? If that is true, what is the benefit of using AsyncHttpClient?

AsyncHttpClient httpClient = new AsyncHttpClient();
ListenableFuture<Response> futureResponse = httpClient.execute(url, payload, headers);

// If this is immediately on next line, am I getting any benefit?
Response response = futureResponse.get();   

Answer 1

Per the Future interface contract, which ListenableFuture implements, get() returns the result of the Future, and thusly must block until necessary computations are complete.

Executing get() immediately after a Future call would give you no benefit, if system A calls system B with an async request, calling get right after will cause system A to wait.

If you want system A to keep doing things while B is processing the request, you may wish to add a Callback or Listener to the ListenableFuture so that A can do what it needs to do when B comes back (the ability to do this is kind of the reason why ListenableFuture exists, as a matter of fact).