[JAVA]Repaint method not working

I have ventured into the lands of java for the first time and i am starting with a simple pong game, the problem is that when i draw the ball and set the coordinates to move in a loop, the ball that is drawn on the screen won't show at the new coordinates (wont repaint). I know that i have to repaint the JPanel but i can't figure out what is wrong with my code. This is a java application not applet(don't know if it matters)

P.S if you have any other suggestions please say so, because i'm not very advanced in correct ways to do stuff

Code:

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;


public class mainclass extends JPanel implements Runnable {
    int x, y;

    public static void main(String[] args) {
        JFrame f = new JFrame("area to draw");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainclass p = new mainclass();
        f.add(p);
        f.setSize(200, 200);
        f.setVisible(true);
        Thread t1 = new Thread(new mainclass());
        t1.start();
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.CYAN);
        g.fillOval(x, y, 10, 10);
    }

    @Override
    public void run() {
        while (true) {
//just threw in the print to make sure that the point were updating, which they are
            System.out.println("new" + x + y);
            x = x + 1;
            y = y + 1;
            this.repaint();

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {

            }

        }
    }
}

Thanks in advance

 

since i have posted this i have accomplished my pong game using a screenmanager class i found online (EXTREMELY USEFUL) it implements an excelent double buffering scheme and uses a different method to repaint, however i will leave my original question up because i believe that that code should work and i still would like to know why it doesnt

 

i don't understand what do i need a listener on, and why

 

yes i understand what a listener does but the paintComponent is a built in method of a java panel so when i call repaint() it should update the panel (but it didn't so i was confused)