[rules-users] Some Problem with drools-persistence-jpa Library

Hi list, The attachment is a very simple test case to demonstrate an application using Drools Persistence JPA (5.1.1). Usage: 1. set up a mysql database called framework 2. set the user/password are root/root (or change the bitronix-datasources.properties file) 3. run maven test The core lines are as following: StatefulKnowledgeSession ksession = JPAKnowledgeService.newStatefulKnowledgeSession(kbase, conf, env); ProcessInstance pi = ksession.startProcess("com.zyeeda.system.TestFlow"); pi.signalEvent("signal", "goon"); When executing the 3rd line, an exception occurred java.lang.NullPointerException at org.drools.process.instance.impl.ProcessInstanceImpl.getProcess(ProcessInstanceImpl.java:67) at org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.getWorkflowProcess(WorkflowProcessInstanceImpl.java:185) at org.drools.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:346) at com.zyeeda.test.AppTest.testProcessPersistence(AppTest.java:84) I've headed into the code and find that some working memory related to the ProcessInstanceImpl is null. (drools-core/src/main/java/org/drools/process/instance/impl/ProcessInstanceImpl.java) But I cannot get why this does happen. Please give me some tips. I tried to google some solutions, but find only this one ( http://drools-java-rules-engine.46999.n3.nabble.com/Drools-Flow-Events-No...), but it seems that he solved this problem by using a custom command. Thank you! -- 唐睿