[rules-users] drools leaving a backgroud thread

Hi, I have a Java servlet running on Tomcat7 which runs multiple drools knowledge bases with a session associated to each one. I am using drools version 6.1.0.Beta3 When tomcat shuts-down I am seeing this message in the log: Jun 10, 2014 6:39:36 PM org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks SEVERE: The web application [/MyRulesServlet-1.0-SNAPSHOT] created a ThreadLocal with key of type [org.drools.core.common.UpgradableReentrantReadWriteLock$1] (value [org.drools.core.common.UpgradableReentrantReadWriteLock$1@5c0bf171<mailto:1@5c0bf171>]) and a value of type [org.drools.core.common.UpgradableReentrantReadWriteLock.LockRequestCounter] (value [org.drools.core.common.UpgradableReentrantReadWriteLock$LockRequestCounter@141860ed<mailto:LockRequestCounter@141860ed>]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak. It seems I am not performing a proper cleanup of resources on shutdown. I am calling kSession.dispose() for all the sessions I have, but apparently this is not enough. What else do I need to do to get rid of this background thread? Thanks, Aliza