I have 2 objects, Foo and Bar. Foo can store an instance of Bar. I am trying to create a list of all the Bar objects that correspond to all the Foo objects with a given name. the line in my rule I am using is: Foo($name : Name) $list : List() from accumulate( Foo( Name == $name, $b : Bar != null), collectList($b)) Yet when I print out the list, it includes null elements. But if I instead make the rule: $list : List() from accumulate( Foo( Name == $name, $b : Bar != null), collectList($b!=null)) I get false for all the null Bar objects. Am I missing something? -- View this message in context: http://drools.46999.n3.nabble.com/having-trouble-using-accumulate-to-crea... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users