Assume the existence of an interface, ActionListener, with the following method: - actionPerformed: void-returning, accepts no parameters Define a class, GUIApplication, that implements the above interface and has the following members: - an instance variable, doc, of type Document - a constructor that accepts a Document parameter used to initialize the instance variable - an implementation of the actionPerformed method that invokes the method, save, with the document instance variable as the receiver and sends the message "document saved" to System. out