22.4. Using Menus with Frames
Menus are an integral part of GUIs. Menus allow the user to perform actions without unnecessarily cluttering a GUI with extra components. In Swing GUIs, menus can be attached only to objects of the classes that provide method setJMenuBar. Two such classes are JFrame and JApplet. The classes used to declare menus are JMenuBar, JMenu, JMenuItem, JCheckBoxMenuItem and class JRadioButtonMenuItem.
Look-and-Feel Observation 22.2
Menus simplify GUIs because components can be hidden within them. These components will be visible only when the user looks for them by selecting the menu.
Class JMenuBar (a subclass of JComponent ...