here the exception trace :
Caused by: java.lang.IllegalStateException: Illegal method call. This session was previously disposed.
at org.drools.reteoo.DisposedReteooWorkingMemory.getSessionClock(DisposedReteooWorkingMemory.java:398)
at org.drools.impl.StatefulKnowledgeSessionImpl.getSessionClock(StatefulKnowledgeSessionImpl.java:256)
at org.drools.marshalling.impl.ProtobufMarshaller.marshall(ProtobufMarshaller.java:151)
at org.drools.persistence.SessionMarshallingHelper.getSnapshot(SessionMarshallingHelper.java:72)
at org.drools.persistence.info.SessionInfo.update(SessionInfo.java:85)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.hibernate.ejb.event.BeanCallback.invoke(BeanCallback.java:23)
at org.hibernate.ejb.event.EntityCallbackHandler.callback(EntityCallbackHandler.java:80)
at org.hibernate.ejb.event.EntityCallbackHandler.preUpdate(EntityCallbackHandler.java:65)
at org.hibernate.ejb.event.EJB3FlushEntityEventListener.invokeInterceptor(EJB3FlushEntityEventListener.java:41)
at org.hibernate.event.def.DefaultFlushEntityEventListener.handleInterception(DefaultFlushEntityEventListener.java:330)
at org.hibernate.event.def.DefaultFlushEntityEventListener.scheduleUpdate(DefaultFlushEntityEventListener.java:270)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:151)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:219)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:99)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:49)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027)