Swing/AWT/SWT :: Using JFrame Class In GUI Designing

I have one question that suppose I am designing a Swing applications and I am using JFrame as Top level container.

So what is best

1)first Extends that class like

public class A Extends JFrame
{
//Do all stuff with Top Level container with gui
}

2)Or design like this from this source

[URL] ....

package components;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* TopLevelDemo.java requires no other files. */
public class TopLevelDemo {
/**
* Create the GUI and show it. For thread safety, this method should be invoked from the event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.

[Code] .....