Miloud Haimoune [https://community.jboss.org/people/milhaim] created the discussion "NullPointerException when loading the ksession (Unable to load session snapshot)" To view the discussion, visit: https://community.jboss.org/message/734562#734562 -------------------------------------------------------------- Hi all, I am facing the following issue: When loading the ksession from the data base (I'm using persisted ksession), after restarting the jboss AS this exception happens: INFO  [ProcessManager] Loading session data ... 14:14:40,457 ERROR [SingleSessionCommandService] Could not commit session java.lang.RuntimeException: Unable to load session snapshot     at org.drools.persistence.SessionMarshallingHelper.loadSnapshot(SessionMarshallingHelper.java:96)     at org.drools.persistence.SingleSessionCommandService.initKsession(SingleSessionCommandService.java:238)     at org.drools.persistence.SingleSessionCommandService.<init>(SingleSessionCommandService.java:191)     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)     at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)     at java.lang.reflect.Constructor.newInstance(Constructor.java:513)     at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.buildCommandService(KnowledgeStoreServiceImpl.java:101)     at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.loadStatefulKnowledgeSession(KnowledgeStoreServiceImpl.java:84) ......   Caused by: java.lang.NullPointerException     at org.drools.marshalling.impl.InputMarshaller.readActivation(InputMarshaller.java:1000)     at org.drools.marshalling.impl.InputMarshaller.readActivations(InputMarshaller.java:981)     at org.drools.marshalling.impl.InputMarshaller.readSession(InputMarshaller.java:281)     at org.drools.marshalling.impl.InputMarshaller.readSession(InputMarshaller.java:196)     at org.drools.marshalling.impl.DefaultMarshaller.unmarshall(DefaultMarshaller.java:93)     at org.drools.persistence.SessionMarshallingHelper.loadSnapshot(SessionMarshallingHelper.java:91) it happens when jbpm try to unmarshall the filed +*rulesbytearray*+ (sessionInfo table) when loading the ksession. I have this issue only when I update the drools or the process definition file (using guvnor) and restart the jboss AS (but not all the time). I'm working with jbpm 5.2 final and Jboss 5.1 and persisted ksession. Any solution or idea will be very helpful. Thank you. -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/734562#734562] Start a new discussion in jBPM at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]