title: How to find classloader leak with free tools?
body: <p>I'm investigating a memory leak in a Tomcat/Spring/Hibernate app which is causing the dreaded "out of permgen" error after a few redployments.  I've downloaded the free version of plumbr, which confirms that I have a classloader leak, but unfortunately I can't afford the $499 to get the detailed report.  Is there a free tool that can perform an equivalent analysis and tell me where to look for it?  Or some other common cause of such leaks that I can investigate?</p>
  
  <p>Steps I've taken so far:</p>
  
  <ul>
  <li>Ensure my JDBC driver is unregistered at context shutdown</li>
  <li>Manually shut down the MySQL driver's AbandonedConnectionCleanupThread (per <a href="https://stackoverflow.com/questions/11872316/tomcat-guice-jdbc-memory-leak">Tomcat Guice/JDBC Memory Leak</a>)</li>
  </ul>
  
  <p>What else might be causing the leak?</p>