Created attachment 603445 [details]
error stacktrace

Having several stateful knowledge sessions configured with JPA and Spring Transaction Manager. When these sessions are being disposed, the exception (see an attachment with the stacktrace) it thrown. This issue is probably connected with https://bugzilla.redhat.com/show_bug.cgi?id=839630, as these exceptions take turns.

Steps to reproduce:
this reproducer (originally for bz846981) should be usable https://github.com/droolsjbpm/droolsjbpm-integration/pull/33

see the method dispose(), the order of the sessions being disposed is important, if no exception is thrown in this method, try to reverse the order of sessions.