Marcelo Zabalet [https://community.jboss.org/people/zabalet] created the discussion "WorkflowProcessInstanceUpgrader throwing ClassCastException: ...CommandBasedStatefulKnowledgeSession cannot be cast to ...InternalKnowledgeRuntime" To view the discussion, visit: https://community.jboss.org/message/789794#789794 -------------------------------------------------------------- Hi people! I'm having this issue trying to upgrade process intances using WorkflowProcessInstanceUpgrader as described at http://docs.jboss.org/jbpm/v5.4/userguide/ch.core-basics.html#d0e2318 http://docs.jboss.org/jbpm/v5.4/userguide/ch.core-basics.html#d0e2318 This is the line creating the knowledgeSession: ksession = JPAKnowledgeService.newStatefulKnowledgeSession(knowledgeBase, null, env); and this is the line trying to upgrade: WorkflowProcessInstanceUpgrader.upgradeProcessInstance(knowledgeSession, processInstance.getId(), newProcessDefinitionId, mapping); Inside https://github.com/droolsjbpm/jbpm/blob/5.4.0.Final/jbpm-flow/src/main/ja... WorkflowProcessInstanceUpgrader there is the casting causing the problem processInstance.setKnowledgeRuntime((InternalKnowledgeRuntime) kruntime); The point is that CommandBasedStatefulKnowledgeSession does not implements InternalKnowledgeRuntime like his counterparts implementing StatefulKnowledgeSession.    _StatefulKnowledgeSession     |__CommandBasedStatefulKnowledgeSession (NOT implements InternalKnowledgeRuntime)     |__StatefulKnowledgeSessionImpl (implements InternalKnowledgeRuntime)     |__StatefulProcessSession (implements InternalKnowledgeRuntime) Then: - Should CommandBasedStatefulKnowledgeSession implement InternalKnowledgeRuntime like his counterparts? - Should I use a different implementation of StatefulKnowledgeSession? - There is a bigger issue around this inherent to the command based nature? (This same issue was somehow asked https://community.jboss.org/message/634907#634907 here (https://community.jboss.org/message/634907#634907) but there was no feedback) TIA. Marcelo. -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/789794#789794] Start a new discussion in jBPM at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]