title: ThreadPoolExecutor with unbounded queue not creating new threads
body: <p>My <code>ThreadPoolExecutor</code> is failing to create new threads.  In fact I wrote a somewhat hacky <code>LinkedBlockingQueue</code> that will accept any task (i.e. it is unbounded) but call an additional handler - which in my application spews warning trace that the pool is behind - which gives me very explicit information that the TPE is refusing to create new threads even though the queue has thousands of entries in it.  My constructor is as follows:  </p>
  
  <pre><code>private final ExecutorService s3UploadPool = 
  new ThreadPoolExecutor(1, 40, 1, TimeUnit.HOURS, unboundedLoggingQueue);
  </code></pre>
  
  <p>Why is it not creating new threads?</p>