title: Is there a way to add a listener to an Executor/Future's?
body: <p>Java : Is there a way to add a listener to an <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/util/concurrent/Executor.html" rel="nofollow"><code>Executor</code></a>?
  I have a collection with <code>Future</code>s which I try to monitorize , as to update some GUI statuses. Currently I am checking in a background thread if there are differences in the submitted/completed tasks, but I am doing this in a <code>while(true){}</code> block and I do not like this approach.</p>