In RHE book chapter 10, Test Yourself question9: True or false: A component subclass that has executed enableEvents() to enable processing of a certain kind of event cannot also use an adapter as a listener for the same kind of event. Ans: false. As my opinion,this question is trying to test a component can implements unlimited listeners.But my question is: the component in this question has extended a super component class, how can it extends another class like adapter class? Can anyone kindly give me a reply to explain that? Thanks a lot!