Re: [rules-users] New in Drools, java.lang.NullPointerException at org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:967)

can you share your rules, so we can take a look at what is happening? The stack trace doesn't offer too much information to be able to analyze what happen. 2011/3/30 Manuel Ortiz <manuel.ortizramos(a)gmail.com&gt; > Hello all! > > I am new in Drools but day by day, test by test, I think I get a bit more > knowledge of how the rule engine works from user point of view. I've been > adding rules to an alarm system, increasing the complexity and functionality > in several steps. Unfortunately in the last step I found the following > NullPointerException inside the rule engine... > > java.lang.NullPointerException > at org.drools.reteoo.AccumulateNode.getFirstMatch(AccumulateNode.java:967) > at > org.drools.reteoo.AccumulateNode.modifyLeftTuple(AccumulateNode.java:329) > at > org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateModifyChildLeftTuple(SingleLeftTupleSinkAdapter.java:239) > at > org.drools.reteoo.AccumulateNode.evaluateResultConstraints(AccumulateNode.java:640) > at > org.drools.reteoo.AccumulateNode.assertObject(AccumulateNode.java:270) > at org.drools.reteoo.BetaNode.modifyObject(BetaNode.java:312) > at > org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:460) > at > org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:428) > at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:160) > at > org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:460) > at > org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:428) > at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:263) > at > org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:172) > at > org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1442) > at > org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1349) > at > org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:183) > at > org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:196) > at > es.simcasva.alarmas.rules.Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0.defaultConsequence(Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0.java:18) > at > es.simcasva.alarmas.rules.Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0DefaultConsequenceInvoker.evaluate(Rule_Test_Negativo_Alarma_Acceso_Portal_Ubicacion_UM_0DefaultConsequenceInvoker.java:44) > at > org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:917) > at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:856) > at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1071) > at > org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:785) > at > org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:751) > at > org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218) > > I've been trying to find the problem, and found a strange interaction > between three rules that makes the null pointer to appear. The alarm system > has many rules now and it is difficult to simplify the scenario, so I just > would like to know what is the funcion of AccumulateNode object in order to > have an idea of the NullPointerException possible cause. > > Can anyone help me? > > Thank you in advance for your time. > > Regards, > > Manuel Ortiz. > > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > -- - CTO @ http://www.plugtree.com - MyJourney @ http://salaboy.wordpress.com - Co-Founder @ http://www.jbug.com.ar - Salatino "Salaboy" Mauricio -