<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=DE-AT link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-GB style='color:#1F497D'>FYI: I tested my application with the latest Drools release 5.2.0.Final and I couldn’t reproduce the problem described below. It seems that it is solved.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='color:#1F497D'>Best regards,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='color:#1F497D'>Wolfgang<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=DE style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Von:</span></b><span lang=DE style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] <b>Im Auftrag von </b>Weiss, Wolfgang<br><b>Gesendet:</b> Dienstag, 21. Juni 2011 10:19<br><b>An:</b> rules-users@lists.jboss.org<br><b>Betreff:</b> [rules-users] NullPointerException in RightTupleIndexHashTable.remove()<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-GB>Hi all!<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>I encountered that null pointer exceptions occur when retracting an object from the working memory. Sometimes the problem occurs sooner sometimes later but it certainly happens. I think it also depends on the workload on the machine. Sometimes the NPE is thrown in 'LeftTupleIndexHashTable' but mainly in 'RightTupleIndexHashTable'. After the exception is thrown, the object to retract is still in the working memory. When I remove the line 'retract($obj)' in my rule, I don't get an exception. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>The problem occurs mainly in this rule, but also in other rules:<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'>rule</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:green'>"remove a cross talk"</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'> agenda-group</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:green'>"evaluation"</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'> activation-group</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:green'>"ag-crossTalk"</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'> lock-on-active</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'>true</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'> salience</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> 40</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'> when</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> $ctf : CrossTalkFact($persID : uniquePersonID, $ctfTimestamp : timestamp)</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> $pers : AnalysisCue(cueType == AnalysisCue.ACTION_STOP_TALKING, uniquePersonID == $persID, timestamp > $ctfTimestamp) </span><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'>from</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> entry-point </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:green'>"LowLevelCueStream"</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'>then</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:#960000'> retract</span></b><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'>($ctf); </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:olive'>//the suspicious line</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:black'> </span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New";color:olive'>//... do some other things</span><span lang=EN-GB style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Courier New";color:#960000'>end</span></b><span lang=EN-GB style='font-family:"Courier New"'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>My configuration:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>drools.dialect.java.compiler = JANINO <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> EventProcessingOption = STREAM <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>I was able to reproduce the problem with following versions:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>5.1.1 <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> 5.2.0.M1 <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> 5.2.0.CR1 <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>Stack trace from the version: 5.2.0.CR1<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>org.drools.runtime.rule.ConsequenceException: rule: remove a cross talk<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:915)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:844)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1055)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:733)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:699)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> ...<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>Caused by: java.lang.NullPointerException<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.core.util.RightTupleIndexHashTable.remove(RightTupleIndexHashTable.java:351)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.NotNode.retractRightTuple(NotNode.java:178)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:235)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.EntryPointNode.retractObject(EntryPointNode.java:229)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.NamedEntryPoint.retract(NamedEntryPoint.java:529)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:226)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at eu.ta2.orchestration.engine.cueLifter.Rule_remove_a_cross_talk_0.defaultConsequence(Unknown Source)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at eu.ta2.orchestration.engine.cueLifter.Rule_remove_a_cross_talk_0DefaultConsequenceInvoker.evaluate(Unknown Source)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:905)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> ... 31 more<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>Sometimes the exception occurs in the LeftTupleIndexHashTable:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>org.drools.runtime.rule.ConsequenceException: rule: remove a cross talk<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:915)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:844)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1055)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:733)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:699)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> ...<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>Caused by: java.lang.NullPointerException<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.core.util.LeftTupleIndexHashTable.remove(LeftTupleIndexHashTable.java:275)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.NotNode.retractLeftTuple(NotNode.java:231)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateRetractLeftTuple(SingleLeftTupleSinkAdapter.java:212)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateRetractLeftTuple(SingleLeftTupleSinkAdapter.java:86)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.JoinNode.retractLeftTuple(JoinNode.java:210)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.SingleLeftTupleSinkAdapter.doPropagateRetractLeftTuple(SingleLeftTupleSinkAdapter.java:212)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.SingleLeftTupleSinkAdapter.propagateRetractRightTuple(SingleLeftTupleSinkAdapter.java:119)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.JoinNode.retractRightTuple(JoinNode.java:192)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:235)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.reteoo.EntryPointNode.retractObject(EntryPointNode.java:229)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.NamedEntryPoint.retract(NamedEntryPoint.java:529)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:226)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at eu.ta2.orchestration.engine.cueLifter.Rule_remove_a_cross_talk_0.defaultConsequence(Unknown Source)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at eu.ta2.orchestration.engine.cueLifter.Rule_remove_a_cross_talk_0DefaultConsequenceInvoker.evaluate(Unknown Source)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:905)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB> ... 31 more<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>Any help is appreciated.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB>Best regards,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB>Wolfgang<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p></div></body></html>