[rules-users] Help debugging NPE

I'm running into an NPE using Drools 4.0.7, and I'm stumped by it (stacktrace below). I made some changes to seemingly unrelated code, and this error started showing up. It would help me to understand what's going on if someone could tell me roughly what's going on here. Since the error is thrown by generated code (in what I assume is a shadow proxy), I can't tell what the offending null pointer is. I'm not even entirely sure what's triggering the bug (it happens half an hour into the run of big multi-threaded application with about 40K objects in the working memory). Is this happening because: *) getRli_nums() in one of my PRRecord objects is returning a null value? *) There is a null PRRecord object backing the shadow proxy? *) Some other thing is null? *) I'm running into a bug in Drools? I stuck in this rule: when $pr : PRRecord( rli_nums == null ) then System.out.println($pr.getId()); end And it didn't print anything, so I'm inclined to think that this is not a simple matter of something returning a null value... I'll be most appreciative of any help I can get. Here's the stacktrace: java.lang.NullPointerException at org.drools.base.net.juniper.dash.data.PRRecord13409648$getRli_nums.getValue(Unknown Source) at org.drools.base.ClassFieldExtractor.getValue(ClassFieldExtractor.java:127) at org.drools.base.evaluators.BaseMemberOfEvaluator.evaluateCachedRight(BaseMemberOfEvaluator.java:45) at org.drools.rule.VariableRestriction.isAllowedCachedRight(VariableRestriction.java:89) at org.drools.rule.VariableConstraint.isAllowedCachedRight(VariableConstraint.java:81) at org.drools.common.DoubleBetaConstraints.isAllowedCachedRight(DoubleBetaConstraints.java:164) at org.drools.reteoo.JoinNode.retractObject(JoinNode.java:189) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateRetractObject(CompositeObjectSinkAdapter.java:375) at org.drools.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:189) at org.drools.reteoo.Rete.retractObject(Rete.java:215) at org.drools.reteoo.ReteooRuleBase.retractObject(ReteooRuleBase.java:211) at org.drools.reteoo.ReteooWorkingMemory.doRetract(ReteooWorkingMemory.java:79) at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1250) at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1203) at net.juniper.dash.data.DataSource.reconcileAssertedRecords(DataSource.java:409) -- Dirk Bergstrom dirk(a)juniper.net _____________________________________________ Juniper Networks Inc., Computer Geek Tel: 408.745.3182 Fax: 408.745.8905