707: Mainline

The program shown in Segment 702 has the following structure:

import java.awt.event.*; 
public class application name extends JFrame{ 
 public static void main (String argv []) { 
  new application name (); 
 } 
 public application name () { 
  // Call superclass constructor 
  // Establish window size 
  // Create and connect class instances 
  // Show the window 
 } 
 // Define inner classes 
} 

In the program shown in Segment 702, there are no class instances other than instances of the MovieApplication and the LocalWindowListener, so there is not much to connect. Nevertheless, both that program and the structure shown in this segment illustrate the following extremely common characteristics:

• The application class is defined to be a subclass of the JFrame class.
• The main method launches the application by creating an instance of the application class.
• The application-class's constructor titles, sizes, and displays a window.
• The application-class's constructor creates class instances as required by the application.
• The application-class's constructor connects appropriately all the required class instances.