Java Callable : What happens to the thread before get() is called

Question

More precisely : If I start async computation by calling submit(Callable<T> task) method on an ExecutorService (itself constructed with Executors.newCachedThreadPool()), I can wait for the computation to finish and retrieve the result by calling Future.get().

My question is : if the computation is already finished, what happens until I call get()? Does the thread is blocked until I retrieved the result? Does the result is stored and the thread assigned to another task? Something completely different?

Thanks in advance for you answers

Answer 1

No, Thread is not blocked, it is returned to the pool. In general it is the get() calling thread dependant on worker, not the other way around. So if there is a result, return it, if not, wait until it will be available.