drainDeadlock.java

private final Queue<Runnable> tasks = new MpscArrayQueue<>(64);
private final ReentrantLock lock = new ReentrantLock();
private final Condition condition = lock.newCondition();
private volatile boolean running = true;
private final Thread executorThread = new Thread(() -> {
    do {
        running = true;
        Runnable task;
        while ((task = tasks.poll()) != null) {
            try {
                task.run();
            } catch (Throwable t) {
                t.printStackTrace();
            }
        }
        running = false;
        if (!tasks.isEmpty()) {
          continue;
        }
        lock.lock();
        try {
              try {
                  condition.await();
              } catch (InterruptedException e) {
                  Thread.currentThread().interrupt();
                  //NOOP
              }            
        } finally {
            lock.unlock();
        }
    } while (!Thread.interrupted());
    //simple eh? :P
    tasks.clear();
});