So, you can have Client.class just in war files. ejb3 archive could still be hot-deployed at any time as far as the class still implements Client interface. Call-by-value has nothing with it because if you deploy Client.class in different packages then it has got different classloaders which causes that they are not the same class for JVM and cannot be casted. Sohil gave an idea to move classes from your lib jar to WEB-INF/classes and check whether it works. Moreover, we don't see any application.xml in this ear definition. Maybe you could achieve loading lib jar only once by defining it there. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3961117#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...