title: What are those java threads starting with "pool"?
body: <p>I have a problem with a Tomcat server that is unable to shutdown gracefully. I have taken a thread dump after I issued the shutdown command, and it looks like this:</p>
  
  <p><a href="http://pastebin.com/7SW4wZN9" rel="noreferrer">http://pastebin.com/7SW4wZN9</a></p>
  
  <p>The thread which I believe is the "suspect" that does not allow the VM to shut down is the one named "pool-4-thread-1". The rest of them are either daemon threads or internal VM threads. While trying to find out what this thread is for, I noticed that there are other java programs out there that create threads with similar names (For example, JVisualVM creates such threads).</p>
  
  <p>So I'm wondering if someone else knows what this thread is and how it can be created.</p>