I think you must be inserting more than one object into your session. You should be doing something like: kSession.insert(fileData); kSession.fireAllRules(); -- View this message in context: http://drools.46999.n3.nabble.com/rules-users-problem-with-drools-tp4028402p4028419.html Sent from the Drools: User forum mailing list archive at Nabble.com.