[rules-users] UnsupportedOperationException intermitently

We've upgraded Drools 5.1 to 5.4.0.Final. Everything is great with new incremental build change-set.However, occasionally we get this error (so far, 2 different stack trace)java.lang.UnsupportedOperationException at org.drools.reteoo.BaseLeftTuple.getObject(BaseLeftTuple.java:589) at org.drools.reteoo.RuleTerminalNode.modifyLeftTuple(RuleTerminalNode.java:273) at org.drools.reteoo.LeftTupleSource.doModifyLeftTuple(LeftTupleSource.java:297) at org.drools.reteoo.AbstractTerminalNode.modifyLeftTuple(AbstractTerminalNode.java:104) at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateModifyObject(CompositeLeftTupleSinkAdapter.java:260) at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateModifyObject(CompositeLeftTupleSinkAdapter.java:275) at org.drools.reteoo.LeftInputAdapterNode.modifyObject(LeftInputAdapterNode.java:170) at org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68) at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157) at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:432) at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157) at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421) at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314) at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265) at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470) at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:370) at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:317) at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:312)AND java.lang.UnsupportedOperationException at org.drools.reteoo.BaseLeftTuple.getPrevious(BaseLeftTuple.java:478) at org.drools.core.util.LeftTupleList.remove(LeftTupleList.java:84) at org.drools.core.util.LeftTupleList.removeAdd(LeftTupleList.java:65) at org.drools.reteoo.JoinNode.modifyLeftTuple(JoinNode.java:302) at org.drools.reteoo.LeftTupleSource.doModifyLeftTuple(LeftTupleSource.java:297) at org.drools.reteoo.LeftTupleSource.modifyLeftTuple(LeftTupleSource.java:271) at org.drools.reteoo.JoinNode.modifyLeftTuple(JoinNode.java:429) at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateModifyObject(CompositeLeftTupleSinkAdapter.java:260) at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateModifyObject(CompositeLeftTupleSinkAdapter.java:275) at org.drools.reteoo.LeftInputAdapterNode.modifyObject(LeftInputAdapterNode.java:170) at org.drools.reteoo.SingleObjectSinkAdapter.propagateModifyObject(SingleObjectSinkAdapter.java:68) at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157) at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:432) at org.drools.reteoo.AlphaNode.modifyObject(AlphaNode.java:157) at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateModifyObject(CompositeObjectSinkAdapter.java:507) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateModifyObject(CompositeObjectSinkAdapter.java:421) at org.drools.reteoo.ObjectTypeNode.modifyObject(ObjectTypeNode.java:314) at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:265) at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:470) at org.drools.common.NamedEntryPoint.update(NamedEntryPoint.java:370) at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:317) at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:312)I've searched around and saw https://issues.jboss.org/browse/JBRULES-3713. I've downloaded the test program and load our rules but can't reproduce the issue. The similarity between our rules and rules in the test case is that we do have a rule matched and perform an update on the fact.With my limited knowledge of drools and how it works internally, i've run out of ideas.SOS, please help!!!Regards,Trung -- View this message in context: http://drools.46999.n3.nabble.com/UnsupportedOperationException-intermite... Sent from the Drools: User forum mailing list archive at Nabble.com.