Techy, I don't know how you got this exception, but I tried to reproduce it here with 4.0.x branch and was not able to. Also, it is very strange that your exception stack has this: org.drools.base.evaluators.IntegerFactory$IntegerLessEvaluator.evaluate(IntegerFactory.java:241) Suggesting that you are using a "<" evaluator and not an "==" evaluator as your sample. Also, by the stack trace, it seems you are using a bound variable, not an explicit "null" constant. So definitively, it is not the rule you are showing in your e-mail bellow. If you can get an isolated test case that can be reproduced, please open a JIRA and attach the test case and I will investigate. []s Edson 2009/4/28 techy <techluver007(a)gmail.com&gt; > > Hello, > For following rule, NullPointerException is thrown for null id in 4.x. > is > this expected? Please clarify. > > Foo{ > Integer id; > } > Rule "null check" > foo : Foo(id==null) > then > end > > stack trace: > java.lang.NullPointerException > at > > org.drools.base.extractors.BaseObjectClassFieldExtractor.getIntValue(BaseObjectClassFieldExtractor.java:95) > at > > org.drools.base.ClassFieldExtractor.getIntValue(ClassFieldExtractor.java:197) > at > > org.drools.base.evaluators.IntegerFactory$IntegerLessEvaluator.evaluate(IntegerFactory.java:241) > at > org.drools.rule.VariableRestriction.isAllowed(VariableRestriction.java:73) > at > org.drools.rule.VariableConstraint.isAllowed(VariableConstraint.java:67) > at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:137) > at > > org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:318) > at > org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:162) > at org.drools.reteoo.Rete.assertObject(Rete.java:175) > at > org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:192) > at > org.drools.reteoo.ReteooWorkingMemory.doInsert(ReteooWorkingMemory.java:71) > at > > org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:911) > at > > org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:883) > at > > org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:684) > at > > org.drools.reteoo.ReteooStatelessSession.execute(ReteooStatelessSession.java:160) > > -- > View this message in context: > http://www.nabble.com/NullPointerException-for-Integer-null-tp23286041p23... > Sent from the drools - user mailing list archive at Nabble.com. > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > -- Edson Tirelli JBoss Drools Core Development JBoss, a division of Red Hat @ www.jboss.com _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users