Java Swing : Applet Application

import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.HeadlessException;
import javax.swing.JFrame;
import javax.swing.JPanel;

/**
 *
 * @author Amol
 */
public class Jpan extends JFrame{
   
    jpanel j;

    public Jpan() throws HeadlessException {
    super("Swing application");
        Container contentPane = getContentPane();
        j=new jpanel();
        contentPane.add(j);
       
    }
    public static void main(String[] args) {
       final JFrame jf = new Jpan();
        jf.setBounds(100, 100, 300, 300);
    jf.setVisible(true);  
    }
}


class jpan1 extends JPanel{

    public jpan1() {
   
    setBackground(Color.red);
   
    }
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.drawString("Swing using Jpanel and JFrame", 50, 30);
        g.drawString("There is a problem here !", 70, 120);
        g.drawString("\"Closing me won't end the application \"", 35, 150);
       
    }
   
}