Thread deadlock issue in class ProjectClassLoader.java

In our project , we are using drools6.1.0.Final jars and the rules are deployed in a jar. Another application when trying to use the rules jar is getting thread deadlock problem. Stack trace is
at org.drools.core.common.ProjectClassLoader$InternalTypesClassLoader.loadClass(ProjectClassLoader,java284)
Two threads are in deadlock condition on this thread. I restarted the application and the error is gone but we need to fix this issue so that it is not reproduced later.The class is in drools-core jar