RandomCircle

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;
 
public class RandomCircle extends JFrame 
    implements ActionListener {
 
    int xPos, yPos, direction, distance;
        
    private JPanel panel;
    private Random random;
    private javax.swing.Timer timer;
 
    public static void main(String[] args) {
        RandomCircle frame = new RandomCircle();
        frame.setSize(800, 800);
        frame.createGUI();
        frame.setVisible(true);
    }
 
    private void createGUI() {
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        Container window = getContentPane();
        window.setLayout(new FlowLayout() );
        random = new Random();
 
        panel = new JPanel();
        panel.setPreferredSize(new Dimension(700, 700));
        panel.setBackground(Color.lightGray);
        window.add(panel);
        
        timer = new javax.swing.Timer(10, this);
        timer.start();
        
        xPos = 350;
        yPos = 350;
        direction = 0;
    }
 
    public void actionPerformed(ActionEvent event) {
        
        Graphics paper = panel.getGraphics();
        paper.setColor(Color.blue);
        paper.drawOval(xPos, yPos, 15, 15);
        direction = random.nextInt(4);
        distance = (random.nextInt(6) + 5) * 2;
        paper.setColor(Color.red);
        paper.fillOval(350, 350, 15, 15);
        
        if (direction == 0) {
            yPos = yPos - distance;
            yPos = (yPos + 685) % 685;
        }
        
        if (direction == 1) {
            yPos = yPos + distance;
            yPos = (yPos + 685) % 685;
        }
        
        if (direction == 2) {
            xPos = xPos + distance;
            xPos = (xPos + 685) % 685;
        }
        
        if (direction == 3) {
            xPos = xPos - distance;
            xPos = (xPos + 685) % 685;
        }
    }
}