Tomcat7 error at shutdown: Smack Keep Alive thread can not be stopped

Hi,

We are using Tomcat 7 for our web application, which is connecting to Openfire server using smack API 3.2.0. When we shutdown Tomcat, we are making sure to call disconnect() on the XMPPConnection object. But we are still seeing the following error in the catalina.out.

SEVERE: The web application [/mywebapp] appears to have started a thread named [Smack Keep Alive (32)] but has failed to stop it. This is very likely to create a memory leak.

  Apr 12, 2013 8:08:47 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads

Actually, we are seeing two SEVERE errors of the above kind. And we have to do a kill -9 on the Tomcat to kill the tomcat process. Any clues on what could be the issue and how we can avoid this? Any helpful information will be greatly appreciated.

Thanks

Yuva