Hi I'm currently working on a program which uses a rule based expert system. I am using eclipse with the expert system shell drools (3.0). The program works fine when I run it in eclipse but when I try to export the program as a jar file it does not seem to work. I did cmd java -jar to find out what's going wrong and it gives me the following error messages: Exception in thread "main" java.lang.NoClassDefFoundError: org/drools/RuleBase at com.sample.GUI.<init>(GUI.java:34) at com.sample.GUI.main(GUI.java:41) and also: Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: org/drool s/RuleBase at com.sample.beakAndBill.actionPerformed(beakAndBill.java:64) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.JToggleButton$ToggleButtonModel.setPressed(Unknown Source ) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased (Unknown Sour ce) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) can anyone help me with this problem. I know that it's probably missing the drools classes and if that is the case can anyone tell me how to add the classes and get the jar to work correctly. Thanks in advance. -- View this message in context: http://www.nabble.com/Exception-in-thread-%22main%22-java.lang.NoClassDef... Sent from the drools - user mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users