code: public void completeExecutorTask()
    {
      ExecutorQueueItem item = null;
  
      synchronized (_executorLock) {
        _executorTaskCount--;
  
        assert(_executorTaskCount >= 0);
  
        if (_executorQueueHead != null) {
          item = _executorQueueHead;
  
          _executorQueueHead = item._next;
  
          if (_executorQueueHead == null)
            _executorQueueTail = null;
        }
      }
  
      if (item != null) {
        Runnable task = item.getRunnable();
        ClassLoader loader = item.getLoader();
  
        boolean isPriority = false;
        boolean isQueue = true;
        boolean isWake = true;
  
        scheduleImpl(task, loader, MAX_EXPIRE, isPriority, isQueue, isWake);
      }
    }
docs: Called when an executor task completes