Elegantly implementing queue length indicators to ExecutorServices

There is a more direct way:

ThreadPoolExecutor executor = new ThreadPoolExecutor( 1, 1, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<Runnable>() );
// add jobs
// ...
int size = executor.getQueue().size();

This is directly copied from Executors.newSingleThreadExecutor in JDK 1.6. The LinkedBlockingQueue that is passed to the constructor is actually the very object that you will get back from getQueue.