how can i know how a task finished when using java's Future class

Question

I'm using the java's Future class to execute a task, but the method isDone returns true if the task completed. Completion may be due to normal termination, an exception, or cancellation -- in all of these cases, this method will return true.

is there a way to know if it ended because an exception or because it finished successfully ?

Answer 1

When you call Future.get() method, there is 4 possible outcomes:

• You get the result value
• You get CancellationException - if the computation was cancelled (e.g. Future.cancel(true) is called)
• You get ExecutionException - if the computation threw an exception
• You get InterruptedException - if the current thread was interrupted while waiting (e.g. executor.shutdownNow() is called)