Having looked at the code, this should not happen unless the target class VacanteVO already contains the method getRequisitos() that you are trying to add with MixinAspectoVacanteVO. Have you already woven the class perhaps? Or are you trying to add several mixins? If more than one mixin contains a method that is the same I think you might get this error View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4150988#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...