import javax.swing.*;
import java.awt.*;

public class Test1 {
int x = 70;
int y = 70;

public static void main (String[] args) {
    Test1 gui = new Test1 ();
    gui.go();
}
public void go() {
    JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    MyDrawPanel drawPanel = new MyDrawPanel();
    frame.getContentPane().add(drawPanel);
    frame.setSize(300,300);
    frame.setVisible(true);

    for (int i = 0; i < 130; i++) {
        x++; y++;
        drawPanel.repaint();
        try { Thread.sleep(50);
        } catch(Exception ex) { } }
}// close go() method

class MyDrawPanel extends JPanel {
    public void paintComponent(Graphics g) {
        g.setColor(Color.green);
        g.fillOval(x,y,40,40);
    }
} // close inner class
} // close outer class