A traffic light in Java, have fun.

import java.awt.*;
public class Ampel {


  // Anfang Attribute
 private boolean rot = true;
 private boolean gelb = false;
 private boolean gruen = false;
 private int x;
 private int y;
  // Ende Attribute

 public Ampel (int x,int y)
 {
              this.x = x;
              this.y = y;
 }

 public void rot(){
  rot = true;
  gelb = false;
  gruen = false;
 }

 public void rotgelb(){
  rot = true;
  gelb = true;
  gruen = false;
 }

 public void gruen(){
  rot = false;
  gelb = false;
  gruen = true;
 }
 
 public void gelb(){
  rot = false;
  gelb = true;
  gruen = false;
 }

  // Anfang Methoden
  public void paint(Graphics g)
              {
              ((Graphics2D)g).setRenderingHint (RenderingHints.KEY_ANTIALIASING,
                                 RenderingHints.VALUE_ANTIALIAS_ON);
              g.setColor(Color.WHITE);
              g.fillRect(10,30,245,730);

              g.setColor(Color.BLACK);

              g.fillRect(x,y, 200,400);


              if (rot) {

               g.setColor(Color.RED);
               g.fillOval(x + 55, y + 30,100,100);
              }
              else {
               g.setColor(Color.DARK_GRAY);
               g.fillOval(x + 55, y + 30,100,100);
              }

              if (gelb) {

               g.setColor(Color.YELLOW);
               g.fillOval(x + 55,y + 150,100,100);
              }
              else {
               g.setColor(Color.DARK_GRAY);
               g.fillOval(x + 55,y + 150,100,100);
              }

              if (gruen) {

               g.setColor(Color.GREEN);
               g.fillOval(x + 55,y + 270,100,100);
              }
              else {
               g.setColor(Color.DARK_GRAY);
               g.fillOval(x + 55,y + 270,100,100);
              }
              }

  public static void main (String[] args) throws InterruptedException{
      }
  // Ende Methoden
      }