New Program

Let us write a new program:

• The frame contains a button.
  • The frame will be the listener for the button.
  • The frame will implement ActionListener.
  • It will have an actionPerformed() method.
• Clicking on the button will exit the program.
  • The actionPerformed() method calls System.exit(0).
• The class of the frame contains the static main() method.

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