Hello drools users. I'm developing a project that uses drools and jbpm2. I have a simple jbpm2 diagram that contains a few workItems, ruleflow groups and gateways. I'm getting the following exception when the process flow goes into first ruleflow-group: java.lang.IncompatibleClassChangeError: Found interface org.drools.reteoo.LeftTuple, but class was expected 2011-09-22 08:54:09,125 INFO [STDOUT] (org.springframework.jms.listener.DefaultMessageListenerContainer#0-1) at tele2Demo.Rule_Load_Data_Tray_0DefaultConsequenceInvoker.evaluate(Rule_Load_Data_Tray_0DefaultConsequenceInvoker.java:17) 2011-09-22 08:54:09,125 INFO [STDOUT] (org.springframework.jms.listener.DefaultMessageListenerContainer#0-1) at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:906) 2011-09-22 08:54:09,125 INFO [STDOUT] (org.springframework.jms.listener.DefaultMessageListenerContainer#0-1) at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:845) 2011-09-22 08:54:09,125 INFO [STDOUT] (org.springframework.jms.listener.DefaultMessageListenerContainer#0-1) at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1056) ... The problem occurs only when I read a ChangeSet.xml from remote guvnor repository. When I read rules from local path the error does not occur. The jars I use: drools-compiler :5.2.0.Final drools-core :5.2.0.Final drools-persistence-jpa :5.2.0.Final knowledge-api-5.2.0.Final jbpm-bpmn2-5.1.0.Final jbpm-flow-5.1.0.Final jbpm-flow-builder-5.1.0.Final jbpm-persistence-5.1.0.Final I verified the history of LeftTuple and indeed it was a class in all 5.2.0 release beside the Final where it was changed to interface. Does anyone here have any idea how to get rid of this error? Are newer versions of jppm packages using LeftTuple interface instead of class? Best regards /danielje -- View this message in context: http://drools.46999.n3.nabble.com/java-lang-IncompatibleClassChangeError-... Sent from the Drools: User forum mailing list archive at Nabble.com.