Create a Frame In java

import javax.swing.*;   // swing class is placed in the javax.swing package
public class Main
{
    public static void main(String[] args)
{
          EmpetyFrame f = new EmpetyFrame(); 
// we create a sub class wd class name empetyframe                      
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// exit upon close event operation

        f.setVisible(true);
 // to show the frame main method calls setvisible method

}
}
class EmpetyFrame extends JFrame
{
public EmpetyFrame( ) 
// constructor sets size
{
setSize(default_width,default_height);
}
public static final int default_width = 300;
public static final int default_height = 300;
}