The problem is in determining the component type when a java.util.Set generic is passed in. In this case its a Set[TestEnum], but the component type is determined to be java.lang.Integer. | 441 DEBUG [DefaultMetaValueFactory] unwrapCollection, type: ReflectClassInfoImpl(a)30cb4b{name=java.util.Set} | 441 DEBUG [DefaultMetaValueFactory] unwrapCollection, componentType: java.lang.Integer | 443 DEBUG [DefaultMetaValueFactory] convertValue failure(For input string: "TWO"), value=TWO, value.class: java.lang.String, typeInfo: java.lang.Integer | Just adding a logging statement can change the failure or even fix the problem. Its some issue with reflection on the generic element type that is suspect. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4190647#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...