Does anybody have any experience in resolving this: Some background: I am trying to retract a fact and before doing that, I checked the object and make sure it is not null. But still, I got null pointer exceptions. A previous developer working with me had posted the problem in Jan 2009. Apparently, there is no final answer in that thread. Here is the old thread: http://lists.jboss.org/pipermail/rules-users/2009-January/007555.html This is my exception: ####<Mar 11, 2010 9:16:24 AM EST> <Error> <HTTP> <epsdatbeal25> <cla-01> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <> <1268316984268> <BEA-101017> <[weblogic.servlet.internal.WebAppServletContext@22fed98 - appName: 'cla', name: 'cla.war', context-path: '/cla-web'] Root cause of ServletException. java.lang.NullPointerException at org.drools.util.RightTupleIndexHashTable.remove(RightTupleIndexHashTable.java:224) at org.drools.reteoo.JoinNode.retractRightTuple(JoinNode.java:204) at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:210) at org.drools.reteoo.EntryPointNode.retractObject(EntryPointNode.java:190) at org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1078) at org.drools.common.AbstractWorkingMemory.retract(AbstractWorkingMemory.java:1045) 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:585) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:301) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:198) at $Proxy42.retract(Unknown Source) Thank you so much! - Eugene Eugene Hsiang Application Architect Reston Office The College Board 11955 Democracy Drive Reston, VA 20190-5662 571-485-3356 (office) 703-796-0817 (Fax) ehsiang@collegeboard.org<mailto:ehsiang@collegeboard.org> www.collegeboard.com Connect to college success