CODEWITHSUNDEEP
javamultithreadingcallable
Sanjeevan
Sanjeevan

Reputation: 67

Isn't exception Drawback of Callable interface?

  1. Why is that we need FutureTask instance when we make thread using callable?

2.I could see that, Using callbale we can get the exception(if occured), using futuretask.get() method. SO in that case, our Main thread should be waiting till the thread is completed!. Will it not destroy the soul purpose of threading? Is it not a drawback of Callable?

Upvotes: 0

Views: 107

Answers (2)

Crazyjavahacking
Crazyjavahacking

Reputation: 9717

The answers:

  1. You don't need FutureTask, you can pass the Callable to ExecutorService.submit().
  2. The get() method is designed to be blocking and it's not the problem. The idea is to execute the functionality in background and meanwhile you can execute other code, you can pass the FutureTask to some other method, etc.
  3. It's important that Callable.call() throws Exception. If you look at the "standard" Runnable it does not throw any checked exception, so in the case of error handling you have to put the exception handling logic in the run() just to compile your program.

Upvotes: 0

Neeraj Jain
Neeraj Jain

Reputation: 7720

V get() throws InterruptedException,ExecutionException

Waits if necessary for the computation to complete, and then retrieves its result.

Now

Why is that we need FutureTask instance when we make thread using callable?

If you need the result of callable then you should use it

our Main thread should be waiting till the thread is completed!

Yes So until and unless you really need the result you should avoid using it

You can also use overloaded version So that wait will not be infinite and you get Timeout Exception as soon as wait() timed out

Upvotes: 1

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