Re: InterruptedException handling

From:
Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 06 Sep 2009 16:18:18 -0700
Message-ID:
<drXom.23482$Y83.2311@newsfe21.iad>
Kenneth P. Turvey wrote:

I used to do a lot of programming in C (still do sometimes) and when a
call was made to sleep there were a number of reasons that it might
return early that had little to do with the program being written. It
was typical to wrap these calls in a loop so that the program would sleep
for the correct amount of time. So when I first moved to Java I would
typically do the same thing with an InterruptedException, catching it and
looping back to the wait or the sleep or whatever had caused the
exception.

The loop is necessary for Object.wait() calls, but InterruptedException
is a different beast.

I think this was a mistake. In Java it seems that the only reason a
thread would be interrupted is do to a direct call to Thread.interrupt
(). So it seems that the best way to handle this exception if it is
unexpected is to let it bubble up through the code like one usually
would.

Or, if you are expecting it as a specific type of signaling device (such
as "abort your current work")

Of course if the code is designed to do something with an
InterruptedException, handling it makes sense, but should it simply be
ignored in code that doesn't expect this to happen? This line of
reasoning also extends to similar exceptions like the BrokenBarrier
exception and others.

Is there any reason to handle InterruptedExceptions as a special case?

Only if you are the owner of the Thread Lifecycle (eg. you have a
contract with the part of the code that is likely to call
Thread.interrupt())

For example, the exception happens in a Callable that is passed to a
ThreadPoolExecutor, you should probably let it propagate. However, if
you are implementing ThreadPoolExecutor, your worker threads may have
special handling for that exception.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

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