title: suspended JVM, "jstack -F pid" only fix
body: <p>JVM gurus,
      Need your help. I have a JVM/app that is getting into a "suspended" state. It sounds similar to this older thread:
  <a href="https://stackoverflow.com/questions/12061226/how-does-jstack-f-affect-a-running-java-process">How does jstack -F affect a running Java process?</a></p>
  
  <p>...but I'm looking for any further suggestions/guidance.</p>
  
  <ul>
  <li>its a commercial java app that (when seemingly idle - middle of the night, etc) becomes unresponsive.</li>
  <li>"kill -3 " hangs, no response in console.</li>
  <li>verbose gc log won't be written to at all.</li>
  <li>'top' shows pid having low (almost no) CPU or memory utilization, low file descriptors, etc.</li>
  <li>jvm remains in this state indefinitely (we left it for 10 hrs once), until...</li>
  <li>"jstack -F " is issued, which kickstarts the JVM/app. GC logging resumes, application starts responding again, etc.</li>
  <li>issue has been occurring for a few weeks, near daily, to 30 independent JVMs (spread across 10 RHEL 6.6 VMs).</li>
  <li>sometimes it happens in a matter of hours after startup. App can be completely unused during that time.</li>
  <li>we've have been using Oracle JVM 1.8.0_31 for Linux x64 to date. Have just upgraded to latest public (1.8.0_72) and will see if issue goes away. </li>
  </ul>
  
  <p>Anyone pointers? Thanks.</p>