New Program

An ordinary button (a button of the JButton class) generates actionEvents and needs an ActionListener that implements actionPerformed(). The actionPerformed() method can call System.exit( 0 ) to exit the program.

Let us write a program that:

• Has a frame that contains one button.
  • The frame will be a listener for the button.
  • The frame will implement ActionListener by having an actionPerformed() method.
• Clicking on the button will exit the program.
  • The actionPerformed() method will call System.exit( 0 ).
• The program will not have a listener for window events.
  • Clicking on the "close button" of the frame will not exit the program.

Often a real application has several ways to quit: the close window button, a menu selection, and perhaps a button like this program.