Sandra Renaud [https://community.jboss.org/people/joploya] created the discussion "Re: getProcess in ProcessInstanceImpl throws a NullPointerException" To view the discussion, visit: https://community.jboss.org/message/806531#806531 -------------------------------------------------------------- Anyone to help please? I don't succed to debug this. This is the code of knowledgeSession producer : log.debug("produce the KnowledgeSession ...");                     KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(); List<Resource> resources = getProcessDefinitionList();                     for (Resource resource : resources) {                               kbuilder.add(resource, ResourceType.BPMN2);                     }                     if ( kbuilder.hasErrors() ) {                          log.error( kbuilder.getErrors().toString() );                      }                     KnowledgeBase kbase = kbuilder.newKnowledgeBase();                     Environment env = KnowledgeBaseFactory.newEnvironment();                     env.set( EnvironmentName.ENTITY_MANAGER_FACTORY, emf );                     if(kbase != null){                               System.out.println("knowledge base NOT null");                               for(org.drools.definition.process.Process p :kbase.getProcesses()){                                         System.out.println(" - process "+p.getName()+" ["+p.getId()+"]");                               }                     }                     StatefulKnowledgeSession ksession = JPAKnowledgeService.newStatefulKnowledgeSession(kbase, null, env);                     System.out.println(" !!!! DEBUG SESSION PERSISTENCE : new session with id : "+ksession.getId()+" !!!!"); And the associated log : knowledge base NOT null - process newcpbeforem29commontrunk [com.st.ams.flows.newcpbeforem29commontrunk] - process newcpbeforem29 [com.st.ams.flows.newcpbeforem29] - process newfinishedgood [com.st.ams.flows.newfinishedgood] - process DataCorrections [com.st.ams.flows.datacorrections] - process newproductline [com.st.ams.flows.newproductline] Hibernate:     insert     into         SessionInfo         (lastModificationDate, rulesByteArray, startDate, OPTLOCK)     values         (?, ?, ?, ?) !!!! DEBUG SESSION PERSISTENCE : new session with id : 32 !!!! After that I try to retrieve all tasks and display task information. This use the method below : public Object getProcessVariable(Long processInstanceId, Long taskId, String key){                     Object retObj = null;                     WorkflowProcessInstance wpi = (WorkflowProcessInstance)kSession.getProcessInstance(processInstanceId);                     if((wpi == null) || (wpi.getVariable(key) == null)){                               System.out.println("workflow process instance is null :-(");                     }else{                               System.out.println("workflow process instance is NOT null :-)");                               retObj = wpi.getVariable(key);                               //node info                               System.out.println("is knowledge runtime null? "+(kSession.getSessionClock() == null));                               System.out.println("list of node instance : ");                               for(NodeInstance iNode : wpi.getNodeInstances()){                                         Node node = iNode.getNode();                               }                     }                     return retObj;           } and the associated log : workflow process instance is NOT null :-) is knowledge runtime null? false list of node instance : but then I have the same error as for my first post in the ProcessInstanceImpl class Caused by: java.lang.NullPointerException           at org.jbpm.process.instance.impl.ProcessInstanceImpl.getProcess(ProcessInstanceImpl.java:68) [jbpm-flow-5.4.0.Final.jar:5.4.0.Final]           at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.getWorkflowProcess(WorkflowProcessInstanceImpl.java:181) [jbpm-flow-5.4.0.Final.jar:5.4.0.Final]           at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.getNodeContainer(WorkflowProcessInstanceImpl.java:69) [jbpm-flow-5.4.0.Final.jar:5.4.0.Final]           at org.jbpm.workflow.instance.impl.NodeInstanceImpl.getNode(NodeInstanceImpl.java:103) [jbpm-flow-5.4.0.Final.jar:5.4.0.Final]           at com.st.ams.task.management.TaskManager.getProcessVariable(TaskManager.java:234) [classes:] It may be the kruntime that is null but how it is null? -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/806531#806531] Start a new discussion in jBPM at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]