Canceling an asynchronous IO operation throws NPE

[Alan Bateman]

Umashankar wrote:
> Hi Alan,
> On canceling an IO operation that is in progress,I get a 
> CancellationException which is expected as per the spec.
> But in the stack trace, I also see a NullPointerException.
> Following is the stack trace.
>    java.util.concurrent.CancellationException
>        at sun.nio.ch.PendingFuture.get(PendingFuture.java:136)
>        at 
> AsyncIOCancelTests.testWrite2FileChannel_01(AsyncIOCancelTests.java:50)
>        at AsyncIOCancelTests.main(AsyncIOCancelTests.java:19)
> Exception in thread "Thread-1" java.lang.NullPointerException
>        at sun.nio.ch.PendingFuture$1.run(PendingFuture.java:206)
>        at 
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) 
>
>        at 
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) 
>
>        at java.lang.Thread.run(Thread.java:674)
>
> Please let me know if this is correct.
There's a bug here - thanks! It arises when you cancel an I/O operation 
that doesn't have a CompletionHandler but the code is trying to invoke 
its cancelled method. It should be harmless (meaning an annoyance 
printed to the console) and I'll fix it for the next build.

-Alan.