Something

/*
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 */

import java.applet.*;
import java.awt.*;

// this line inherits applet class from the class Applet
public class FirstApplet extends Applet {

    int x_pos = 10;
    int y_pos = 100;
    int radius = 20;
    private Image dbImage;
    private Graphics dbg;
            
    public void run() {

        // lower ThreadPriority
        Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
        while (true) {
            // changing the x - position of the ball/circle
            x_pos++;

            // repaint the applet
            repaint();

            try {
                // Stop thread for 20 milliseconds
                Thread.sleep(20);
            } catch (InterruptedException ex) {
            //do nothing
            }

            // set ThreadPriority to maximum value
            Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
        }
    }

    // Double buffering - allows smooth animations
    public void update(Graphics g) {

        if (dbImage == null) {
            dbImage = createImage(this.getSize().width, this.getSize().height);
            dbg = dbImage.getGraphics();
        }

        // clear screen in background
        dbg.setColor(getBackground());
        dbg.fillRect(0, 0, this.getSize().width, this.getSize().height);

        // draw elements in background
        dbg.setColor(getForeground());
        paint(dbg);

        // draw image on the screen
        g.drawImage(dbImage, 0, 0, this);
    }

    public void paint(Graphics g) {
        // set color
        g.setColor(Color.red);

        // paint a filled colored circle
        g.fillOval(x_pos - radius, y_pos - radius, 2 * radius, 2 * radius);


    }
}