Code Review 7091003: ScheduledExecutorService never executes Runnable with corePoolSize of zero (original) (raw)

David Holmes david.holmes at oracle.com
Thu Sep 22 21:45:42 UTC 2011

Sorry Doug/Chris I should have seen this previously, the order here is wrong:

1552 void ensurePrestart() { 1553 int wc = workerCountOf(ctl.get()); 1554 if (wc == 0) 1555 addWorker(null, false); 1556 else if (wc < corePoolSize) 1557 addWorker(null, true); 1558 }

this will always mark the first worker as non-core even if the corePoolSize is > 0. It needs to be swapped

  void ensurePrestart() {
      int wc = workerCountOf(ctl.get());
      if (wc < corePoolSize)
          addWorker(null, true);
      else if (wc == 0)  // corePoolSize must be 0
          addWorker(null, false);
  }

David

On 23/09/2011 2:54 AM, Chris Hegarty wrote:

This change is coming from Doug Lea's CVS and I've already review it.

It seems that in the re-work that was done for Java 7 we dropped this corner case. STPE.delayedExecute will add the task to the work queue and invoke prestartCoreThread. But prestartCoreThread checks for the worker count (0) being less than corePoolSize (0) and as that is not the case nothing happens. So we have a task in the queue but no thread waiting to execute it. For STPE when the queue is not empty there must always be at least one thread waiting on the queue. http://cr.openjdk.java.net/~chegar/7091003/webrev.00/webrev/ -Chris.

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