Hi, I'm still having issues with this despite getting the snapshot update to the mvel jar. Can anyone suggest what else to try please? Am I doing something wrong? Say I insert 2 objects: - ObjectWithKey which has a field that is a string to be used as the key. - ObjectWithMap has a field that is a map, which contains entries - including one for the key string that's in the inserted ObjectWithKey. With the rule below, trying to get the value with the key always produces null (although with the updated jar at least I no longer get a compilation error!). However if I use a literal for the key, or from an inserted String object (the commented out $s below), then it works to print out the right value for the key. rule "Tester" dialect "mvel" when # $s : String (this == "aString") # works if I use $s as key $a : ObjectWithKey ( $k: aStringForKey, $o: objectWithMap ) $b: ObjectWithMap ( this == $o, map != null # works fine, it can see there's a map in existence # map[$k] != null, # no good, Drools thinks this value is always null # map[$s] # this works however ) then System.out.println("ObjectWithMap has non-null map, value for key is "); # prints OK System.out.println($b.map[$k]); # prints out null! end I'm at my wit's end. I've also tried Java (with get) and eval alternatives and can't get it to work. If anyone can suggest a way to get a value out of the map (for testing against other conditions) when the map is a field of one object, using a key that is a field in another object, I'd really appreciate it. Cheers -- View this message in context: http://www.nabble.com/Maps-again---key-derived-from-another-object-tp2509... Sent from the drools - user mailing list archive at Nabble.com.