[jboss-jira] [JBoss JIRA] Resolved: (JBRULES-3224) ClassCastException when comparing class type attributes to null

ClassCastException when comparing class type attributes to null --------------------------------------------------------------- Key: JBRULES-3224 URL: https://issues.jboss.org/browse/JBRULES-3224 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Components: drools-core Affects Versions: 5.3.0.CR1 Reporter: Edson Tirelli Assignee: Edson Tirelli Fix For: 5.3.0.Final, 5.4.0.Beta1 Reported by Thomas: ============================ I've just tried upgrading from Drools 5.3.0-CR1 from the beta and I've hit a regression. JBoss seems to have been down for most of today so I haven't been able to raise a Jira for it. In our model we have Facts which contain fields of java.lang.class, we then have a rule which checks that they aren't null. Eg Fact { Class<Object> classField} Rule "xyz" When Fact(classField != null) Then ... End This is giving the following exception Caused by: java.lang.ClassCastException: org.drools.base.field.ObjectFieldImpl cannot be cast to org.drools.base.field.ClassFieldImpl at org.drools.base.evaluators.EqualityEvaluatorsDefinition$ClassEqualEvaluator.evaluate(EqualityEvaluatorsDefinition.java:1772) at org.drools.rule.LiteralRestriction.isAllowed(LiteralRestriction.java:87) at org.drools.rule.LiteralConstraint.isAllowed(LiteralConstraint.java:109) at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:130) at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:451) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:369) at org.drools.reteoo.AlphaNode.assertObject(AlphaNode.java:134) at org.drools.reteoo.CompositeObjectSinkAdapter.doPropagateAssertObject(CompositeObjectSinkAdapter.java:451) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:379) at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:204) at org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:244) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:330) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:291) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:882) at org.drools.base.DefaultKnowledgeHelper.insert(DefaultKnowledgeHelper.java:180) ... 149 more Wrapping the classField != null within an eval appears to be a work around. This is in the suspect method: public boolean evaluate(InternalWorkingMemory workingMemory, final InternalReadAccessor extractor, final Object object1, final FieldValue object2) { Object value1 = extractor.getValue( workingMemory, object1 ); Object value2 = object2.getValue(); if ( value2 == null ) { ClassFieldImpl classField = (ClassFieldImpl) object2; value2 = classField.resolve( workingMemory ); } return comparator.equals( value1, value2 ); } I think the if statement just needs an instanceof check as well or some other way to track the fact that null may be a valid value to be comparing with!