Before JDK 6 JMenu, JPopupMenu, and JToolbar's protected method createActionComponent(Action) not only created components, but also populated that component with properties of Action, passed as a parameter. Starting from JDK 6, component is created, but it's properties are populated in ?add(Action) method?. Current documentation supports both of behaviours. It should be more clear, which method is responsible for what.

This affects compatibility:
If developer override createActionComponent() is he responsible for populating component properties?