RE: [rules-users] Interesting null pointer exception when inserting afact.

I'm no expert but recall there can be problems running "long running" (subjective) code from AWT's worker thread. I thought it was good practice to run your "application code" in a worker thread. This was the first google hit I had on the matter. http://www.cs.helsinki.fi/u/vihavain/k03/Java/JavathreadsandGUI.html Cheers, Mike _____ From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Edson Tirelli Sent: 08 March 2008 13:15 To: Rules Users List Subject: Re: [rules-users] Interesting null pointer exception when inserting afact. Jason, Can you please isolate and show us the rule that is creating the problem? It is happening either in a eval() statement or in a nested property access. []s Edson 2008/3/7, Jason Partyka <Jason.Partyka(a)hightowerinc.com&gt;: Hi, This is in relation to drools 4.0.4 I have an interesting problem. I am getting a null pointer exception when I am inserting a fact into a StatefulSession object. What is odd about this NPE is that, as far as I can tell (and I have inserted a breakpoint right before I insert the fact) that all the properties in the object are initialized, and there are no rules accessing any thing that could be null. So here's my exception trace (just first few lines to get context): Exception in thread "AWT-EventQueue-0" org.drools.RuntimeDroolsException: java.lang.NullPointerException at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:76) at org.drools.reteoo.EvalConditionNode.assertTuple(EvalConditionNode.java:145) at org.drools.reteoo.SingleTupleSinkAdapter.createAndPropagateAssertTuple(Singl eTupleSinkAdapter.java:55) at org.drools.reteoo.LeftInputAdapterNode.assertObject(LeftInputAdapterNode.jav a:116) at org.drools.reteoo.SingleObjectSinkAdapter.propagateAssertObject(SingleObject SinkAdapter.java:22) at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:153) at org.drools.reteoo.Rete.assertObject(Rete.java:177) at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192) at org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:71) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:88 6) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:85 8) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:65 9) at com.hightower.drools.executablerules.Rules.setTemplate(Rules.java:112) .... Caused by: java.lang.NullPointerException at org.drools.base.mvel.MVELEvalExpression.evaluate(MVELEvalExpression.java:39) at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:72) ... 39 more (that setTemplate method is not a drools template) Any ideas? Thanks, Jason _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users -- Edson Tirelli JBoss Drools Core Development Office: +55 11 3529-6000 Mobile: +55 11 9287-5646 JBoss, a division of Red Hat @ www.jboss.com