completable-future

I know that CompletableFuture design does not control its execution with interruptions, but I suppose some of you might have this problem. CompletableFuture s are very good way to compose async execution, but given the case when you want the underlying execution to be interrupted or stopped when future is canceled, how do we do that? Or we must just accept that any canceled or manually completed CompletableFuture will not impact the thread working out there to complete it? That is, in my opinion, obviously a useless work that takes time of executor worker. I wonder what approach or design

I have 3 CompletableFutures all 3 returning different data types. I am looking to create a result object that is a composition of the result returned by all the 3 futures. So my current working code looks like this: public ClassD getResultClassD() { ClassD resultClass = new ClassD(); CompletableFuture<ClassA> classAFuture = CompletableFuture.supplyAsync(() -> service.getClassA() ); CompletableFuture<ClassB> classBFuture = CompletableFuture.supplyAsync(() -> service.getClassB() ); CompletableFuture<ClassC> classCFuture = CompletableFuture.supplyAsync(() -> service.getClassC() );

I am currently using CompletableFuture supplyAsync() method for submitting some tasks to common thread pool. Here is what code snippet looks like: final List<CompletableFuture<List<Test>>> completableFutures = resolvers.stream() .map(resolver -> supplyAsync(() -> task.doWork())) .collect(toList()); CompletableFuture.allOf(completableFutures.toArray(new CompletableFuture[completableFutures.size()])).join(); final List<Test> tests = new ArrayList<>(); completableFutures.stream() .map(completableFuture -> completableFuture.getNow()) .forEach(tests::addAll); I would like to know how below differs

I am playing with Java 8 completable futures. I have the following code: CountDownLatch waitLatch = new CountDownLatch(1); CompletableFuture<?> future = CompletableFuture.runAsync(() -> { try { System.out.println("Wait"); waitLatch.await(); //cancel should interrupt System.out.println("Done"); } catch (InterruptedException e) { System.out.println("Interrupted"); throw new RuntimeException(e); } }); sleep(10); //give it some time to start (ugly, but works) future.cancel(true); System.out.println("Cancel called"); assertTrue(future.isCancelled()); assertTrue(future.isDone()); sleep(100); //give