title: Unusual PermGen error only reproducible on CentOs
body: <p>I am trying to track down the cause of a PermGen error that does not behave like ones I have encountered before.</p>
  
  <p>It occurs when hot deploying (yes I know) into a custom container (yes I know).</p>
  
  <p>When running on a vm with </p>
  
  <ul>
  <li>CentOS release 6.6 (Final)</li>
  <li>"Java HotSpot(TM) 64-Bit Server VM (build 24.76-b04, mixed mode)"</li>
  </ul>
  
  <p>A PermGen error occurs reliably on 5 redeploys.</p>
  
  <p>Running on my Ubuntu 14.04.1 machine with the same version of java I can reploy 100+ times without issue.</p>
  
  <p>The test for the above is fully automated so all JVM flags, versions, code etc are identical.</p>
  
  <p>The hot deployed code starts a JMS listener. I had initially assumed that the issue would be a ThreadLocal created behind the scenes by the jms code holding onto a class reference however</p>
  
  <p>1) In the heap dump I do <strong>not</strong> see classloaders being retained - they seem to be being GC's as expected</p>
  
  <p>2) Permgen is never exhausted on an identical jvm runnning on ubuntu (as discussed above)</p>
  
  <p>It appears that the issue in some way relates to the underlying os.</p>
  
  <p>Any ideas of what could cause this? </p>