Where to catch Exceptions thrown from Callable.call()

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Handling exceptions from Java ExecutorService tasks

I use the ExecutorService from Java for coordinating Threads. For starting the threads I use

pool = new ExecutorService(2);
callableResults = pool.invokeAll(threads);

To collect the result, I use future.get() for each thread. "threads" is a List of Objects from a Class which implements Callable and overrides call().

Now Ive got the following problem. The method call() does throw various specific exceptions. invokeAll() and future.get() throw only InterruptedException.

Where can I catch my specific exceptions which I throw in call()? Or do I have to handle them there? If one of those exceptions is thrown, is the result then a InterruptedException?

I read this before, but I did not see that he uses Callable and call() as well? Maybe Ive overseen it!? edit: correct. Ive overseen it. sorry. — nano7, Mar 02 '12 at 14:25
`Future.get()` throws `InterruptedException` *and* `ExecutionException`. You need to read the javadocs more carefully. — skaffman, Mar 02 '12 at 14:28
The *answer* (http://stackoverflow.com/a/2248166/302916) does. — Brian Roach, Mar 02 '12 at 14:29

score 40 · Accepted Answer · answered Mar 02 '12 at 14:25

40

AFAIR java.util.concurrent.Future.get() will throw ExecutionException if provided callable threw exception in the past (the exception is stored in the Future).

Exception thrown when attempting to retrieve the result of a task that aborted by throwing an exception. This exception can be inspected using the Throwable.getCause() method.

answered Mar 02 '12 at 14:25

Tomasz Nurkiewicz

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The very reason to use `ExecutorService` is its ability to run without blocking. `get()`, on the other hand, is blocking until the task is executed. Seems like this is one of the major drawbacks of `ExecutorService` – Farid Apr 02 '21 at 10:53

Where to catch Exceptions thrown from Callable.call()

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