I'm stumped. I'm trying to implement persistence with Drools-flow, and I'd like to grab the value of a property on a workitem / processinstance, but everytime I try to get the workitem or process instance I end up with the stack trace below.

I'm walking through the source and from what I can tell, this happens anytime I try and grab a property that is annotated with @Lob in an entity class.

My environment is hibernate/mysql/JPA persistence using BTM as a transaction manager.

These are the relevant lines of code:

         ksession = JPAKnowledgeService.loadStatefulKnowledgeSession(ksession.getId(), m_kbase , null, m_environment);
         m_pi = ksession.getProcessInstance(m_pi.getId());

What am I doing wrong?

<pre>
<code>
java.lang.NullPointerException
    at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:89)
    at org.drools.persistence.processinstance.ProcessInstanceInfo.getProcessInstance(ProcessInstanceInfo.java:135)
    at org.drools.persistence.processinstance.JPAProcessInstanceManager.getProcessInstance(JPAProcessInstanceManager.java:62)
    at org.drools.common.AbstractWorkingMemory.getProcessInstance(AbstractWorkingMemory.java:1793)
    at org.drools.impl.StatefulKnowledgeSessionImpl.getProcessInstance(StatefulKnowledgeSessionImpl.java:261)Hibernate: select         at org.drools.command.runtime.process.GetProcessInstanceCommand.execute(GetProcessInstanceCommand.java:29)
    at org.drools.command.runtime.process.GetProcessInstanceCommand.execute(GetProcessInstanceCommand.java:12)
    at org.drools.persistence.session.SingleSessionCommandService.execute(SingleSessionCommandService.java:254)
    at org.drools.command.impl.CommandBasedStatefulKnowledgeSession.getProcessInstance(CommandBasedStatefulKnowledgeSession.java:95)
    at com.thoughtvine.tracks.workflow.TracksFlow.getParameterFromWorkItem(TracksFlow.java:182)
    at com.thoughtvine.tracks.workflow.test.TestTracksFlow.testGetWorkItem(TestTracksFlow.java:118)
    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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
    at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
</code>
</pre>