LeaseRenewer threads still running after shutdown

[rankinc]

I am seeing errors like these in my logs when trying to shut my KCL application down:

2016-06-28 15:19:06,820 [main] [WebappClassLoaderBase] WARN: The web application [ROOT] appears to have started a thread named [LeaseRenewer-14] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 sun.misc.Unsafe.park(Native Method)
 java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
 java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
 java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
 java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1066)
 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
 java.lang.Thread.run(Thread.java:745)

I have traced the problem to the com.amazonaws.services.kinesis.leases.impl.LeaseCoordinator.stop() method, which does not always shutdown the instance's leaseRenewalThreadpool field. (This field can also be final, BTW).

Moving the existing leaseRenewalThreadpool.shutdownNow() statement a few lines down to here seems to do the trick:

leaseRenewalThreadpool.shutdownNow();
synchronized (shutdownLock) {
    leaseRenewer.clearCurrentlyHeldLeases();
    running = false;
}

See pull #84.

[pfifer]

Commented on the PR, but adding here as well.

The fix looks good, and I will be merging the changes in the near future. I don't yet have a an expected date for the next release.

[pfifer]

PR #84 was merged, and released in v1.6.5.