title: Java threads waiting to lock object that isn't (visibly) locked
body: <p>Normally when I ask for a thread dump, the symptoms of a poorly performing system are easily explained; i.e. normally I would be able to see that a number of threads are clearly waiting on a monitor which has been acquired but not released by another.</p>
  
  <p>In this case, I have a lot of threads waiting for a monitor (0x965ad100), but none appears to have that monitor in the first place. The threads in question can be identified with this signature:</p>
  
  <blockquote>
    <p>waiting to lock &lt;0x965ad100> (a uk.gov.dti.og.fox.ConAgent)</p>
  </blockquote>
  
  <p>I've tried Googling this, and all I seem to find are posts that discuss monitors that are locked, nothing about waiting for a monitor that isn't locked.</p>
  
  <p>Thread dump in full: <a href="http://www.basson.at/docs/stackoverflow/thread_dump.txt" rel="nofollow noreferrer">http://www.basson.at/docs/stackoverflow/thread_dump.txt</a></p>
  
  <p>I hope someone here can explain what I'm seeing, or at least point me in the right direction. Thanks in advance for any responses.</p>