listenable_future_example.java

public void listenableFutureWithCallbackExample() {
    ListeningExecutorService executor = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(NUMBER_OF_THREADS));

    Callable<String> asyncTask = new Callable<String>() {
        @Override
        public String call() throws Exception {
            return computeResult();
        }
    };

    ListenableFuture<String> listenableFuture = executor.submit(asyncTask);

    Futures.addCallback(listenableFuture, new FutureCallback<String>() {
        public void onSuccess(String result) {
            doMoreWithTheResultImmediately(result);
        }

        public void onFailure(Throwable thrown) {
            handleFailure(thrown);
        }
    });

    doSomethingElse();

    try {
        String result = listenableFuture.get();
        useResult(result);
    } catch (ExecutionException e) {
        log.error("Task failed", e);
    } catch (InterruptedException e) {
        log.warn("Task interrupted", e);
    }

    executor.shutdown();
}