anonymous wrote : java.lang.NoClassDefFoundError: net/sf/hibernate/collection/List Sometimes the actual reason for a NoClassDefFoundError is because some dependent class is not available in the classpath. Make sure the classes which are accessed by net/sf/hibernate/collection/List (either through extends or import statements or some other means) are available in the classpath. I checked the Hibernate2.x source for this net/sf/hibernate/collection/List class and it shows that this class uses the org.odmg package for which you have to place the odmg-3.0.jar (or an appropriate version of this jar) in the classpath. Make sure you have done that and also check if there are any other additional jar files that need to be in the classpath. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4109198#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...