1- How to get the return value from the Operation.java? It gets error for future.get() which i really don't know what else should i put in the code.
2- Do i need executor.shutdown for this?
Joined: Feb 22, 2012
im wondering, why it works for future.get() when in try and catch method? and not works out in others?
future.get() method throws java.lang.InterruptedException, java.util.concurrent.ExecutionException which either you need to catch it or add throw for these exception in your main method.
I would suggest to have a look on Future Class APIs to understand its behaviour.
And yes, you need to add shutdown() to end the executor service otherwise it will continue to run indefinitely.