Thanks Edson. That helped alot. Can't we execute something simple like: ObjectA(units != families) When both units & families are defined as int in ObjectA with their public get and set methods. This is the exception I am receiving. org.drools.rule.InvalidRulePackage: Unable to return Declaration for identifier 'families' : [Rule name=Rule6, agendaGroup=Rating, salience=0, no-loop=false] Its even showing correctly in drl editor. If I swap the positions of units & families then the same exception is thrown for 'units'. regards, saleem