title: Oracle UCP driver and tomcat: threads failing to stop
body: <p>We are using Oracle the UCP driver (Oracle Universal Connection Pool) in tomcat 6. It is more or less configured like in Oracles <a href="http://www.oracle.com/technetwork/articles/oem/ucp-jdbc-tomcat-355431.html">Howto</a>. The problem is that the driver starts a lot of threads (Thread-0 to 57, UCP-worker-thread-1 to 24) which aren't stopped when the server shuts down - tomcat emits loads of error messages like this:</p>
  
  <blockquote>
    <p>The web application [/xxx] appears to have started a thread named
    [Timer-17] but has failed to stop it. This is very likely to create a
    memory leak.</p>
  </blockquote>
  
  <p>Any idea how to deal with this?</p>