Traffic light repaint not working via button

Question

I created a traffic light, a button is pressed and the colors should cycle yellow>green>yellow>red etc.. as a normal traffic light would
when i press the start button, the repaint(); doesnt work, system.output shows me the number which corresponds to the light changes but somehow the graphics/paint is not updated.
what am i doing wrong?
package test2;<br />
<br />
import java.awt.event.ActionEvent;<br />
import java.awt.event.ActionListener;<br />
import javax.swing.JButton;<br />
import javax.swing.JOptionPane;<br />
import javax.swing.JPanel;<br />
<br />
public class Traffic_Lights extends JPanel implements ActionListener {<br />
<br />
private Light_Controller LightController;<br />
private JButton jStart, jStop;<br />
<br />
public Traffic_Lights() {<br />
jStart = new JButton("START");<br />
jStop = new JButton("EXIT");<br />
<br />
// Register Listeners with buttons<br />
jStart.addActionListener(this);<br />
jStop.addActionListener(this);<br />
LightController = new Light_Controller();<br />
this.add(jStart);<br />
this.add(jStop);<br />
}<br />
// Adding the traffic light<br />
<br />
<br />
/**<br />
* This method traps the button click events<br />
*/<br />
public void actionPerformed(ActionEvent e) {<br />
// Rotate button is clicked<br />
if (e.getSource() == jStart) {<br />
// Change the color displayed<br />
LightController.changeColor();<br />
package test2;<br />
import java.awt.*;<br />
import java.awt.geom.Rectangle2D;<br />
import javax.swing.JComponent;<br />
import javax.swing.JPanel;<br />
<br />
<br />
public class Light_Controller extends JPanel {<br />
<br />
private int lightState = 1;<br />
<br />
<br />
public void changeColor() {<br />
lightState++;<br />
System.out.println(lightState);<br />
if (lightState > 5) {<br />
lightState = 2;<br />
<br />
}<br />
<br />
this.repaint();<br />
<br />
}<br />
<br />
/**<br />
* This method draws the traffic light on the screen<br />
*/<br />
public void paintComponent(Graphics g) {<br />
super.paintComponent(g);<br />
<br />
Graphics2D g1 = (Graphics2D) g;<br />
// Draws the traffic light<br />
// Draw out white frame<br />
g.setColor(new Color(255,255,255));<br />
g.fillRoundRect(35,15,120,225,30,30);<br />
<br />
// Draw inner black frame<br />
g.setColor(new Color(0,0,0));<br />
g.fillRoundRect(50,30,90,195,30,30);<br />
g.drawRoundRect(35,15,120,225,30,30);<br />
<br />
// RED dim<br />
g.setColor(new Color(100,0,0));<br />
g.fillOval(70,40,50,50);<br />
<br />
// YELLOW dim<br />
g.setColor(new Color(100,100,0));<br />
g.fillOval(70,100,50,50);<br />
<br />
// GREEN dim<br />
g.setColor(new Color(0,100,0));<br />
g.fillOval(70,160,50,50);<br />
<br />
// Draw traffic light stand<br />
g.setColor(new Color(50,50,50));<br />
g.fillRect(80,240,30,30);<br />
<br />
switch(lightState) {<br />
case 1:<br />
// red glows<br />
g.setColor(new Color(255, 0, 0));<br />
g.fillOval(70, 40, 50, 50);<br />
g1.fill(new Rectangle2D.Double(440, 450, 60, 5));<br />
g1.fill(new Rectangle2D.Double(350, 240, 60, 5));<br />
g1.fill(new Rectangle2D.Double(345, 360, 5, 80));<br />
g1.fill(new Rectangle2D.Double(500, 250, 5, 90));<br />
break;<br />
<br />
case 2:<br />
// yellow glows<br />
g.setColor(new Color(255, 255, 0));<br />
g.fillOval(70, 100, 50, 50);<br />
g1.fill(new Rectangle2D.Double(440, 450, 60, 5));<br />
g1.fill(new Rectangle2D.Double(350, 240, 60, 5));<br />
g1.fill(new Rectangle2D.Double(345, 360, 5, 80));<br />
g1.fill(new Rectangle2D.Double(500, 250, 5, 90));<br />
break;<br />
<br />
case 3:<br />
// green glows<br />
g.setColor(new Color(0, 255, 0));<br />
g.fillOval(70, 160, 50, 50);<br />
g1.fill(new Rectangle2D.Double(440, 450, 60, 5));<br />
g1.fill(new Rectangle2D.Double(350, 240, 60, 5));<br />
g1.fill(new Rectangle2D.Double(345, 360, 5, 80));<br />
g1.fill(new Rectangle2D.Double(500, 250, 5, 90));<br />
break;<br />
<br />
case 4:<br />
// back to yellow glows<br />
g.setColor(new Color(255, 255, 0));<br />
g.fillOval(70, 100, 50, 50);<br />
g1.fill(new Rectangle2D.Double(440, 450, 60, 5));<br />
g1.fill(new Rectangle2D.Double(350, 240, 60, 5));<br />
g1.fill(new Rectangle2D.Double(345, 360, 5, 80));<br />
g1.fill(new Rectangle2D.Double(500, 250, 5, 90));<br />
break;<br />
<br />
case 5:<br />
// back to red glows<br />
g.setColor(new Color(255, 0, 0));<br />
g.fillOval(70, 40, 50, 50);<br />
g1.fill(new Rectangle2D.Double(440, 450, 60, 5));<br />
g1.fill(new Rectangle2D.Double(350, 240, 60, 5));<br />
g1.fill(new Rectangle2D.Double(345, 360, 5, 80));<br />
g1.fill(new Rectangle2D.Double(500, 250, 5, 90));<br />
break;<br />
}<br />
}<br />
} <br />

Answer 1

Code continued...
class Light_Controller extends JPanel {
    private int lightState = 1;
    public void changeColor() {
        lightState++;
        System.out.println(lightState);
        if (lightState > 5) {
            lightState = 2;
        this.repaint();
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g1 = (Graphics2D) g;
        g.setColor(new Color(255, 255, 255));
        g.fillRoundRect(35, 15, 120, 225, 30, 30);
        g.setColor(new Color(0, 0, 0));
        g.fillRoundRect(50, 30, 90, 195, 30, 30);
        g.drawRoundRect(35, 15, 120, 225, 30, 30);
        g.setColor(new Color(100, 0, 0));
        g.fillOval(70, 40, 50, 50);
        g.setColor(new Color(100, 100, 0));
        g.fillOval(70, 100, 50, 50);
        g.setColor(new Color(0, 100, 0));
        g.fillOval(70, 160, 50, 50);
        g.setColor(new Color(50, 50, 50));
        g.fillRect(80, 240, 30, 30);
        switch (lightState) {
            case 1:
                g.setColor(new Color(255, 0, 0));
                g.fillOval(70, 40, 50, 50);
                g1.fill(new Rectangle2D.Double(440, 450, 60, 5));
                g1.fill(new Rectangle2D.Double(350, 240, 60, 5));
                g1.fill(new Rectangle2D.Double(345, 360, 5, 80));
                g1.fill(new Rectangle2D.Double(500, 250, 5, 90));
                break;
            case 2:
                g.setColor(new Color(255, 255, 0));
                g.fillOval(70, 100, 50, 50);
                g1.fill(new Rectangle2D.Double(440, 450, 60, 5));
                g1.fill(new Rectangle2D.Double(350, 240, 60, 5));
                g1.fill(new Rectangle2D.Double(345, 360, 5, 80));
                g1.fill(new Rectangle2D.Double(500, 250, 5, 90));
                break;
            case 3:
                g.setColor(new Color(0, 255, 0));
                g.fillOval(70, 160, 50, 50);
                g1.fill(new Rectangle2D.Double(440, 450, 60, 5));
                g1.fill(new Rectangle2D.Double(350, 240, 60, 5));
                g1.fill(new Rectangle2D.Double(345, 360, 5, 80));
                g1.fill(new Rectangle2D.Double(500, 250, 5, 90));
                break;
            case 4:
                g.setColor(new Color(255, 255, 0));
                g.fillOval(70, 100, 50, 50);
                g1.fill(new Rectangle2D.Double(440, 450, 60, 5));
                g1.fill(new Rectangle2D.Double(350, 240, 60, 5));
                g1.fill(new Rectangle2D.Double(345, 360, 5, 80));
                g1.fill(new Rectangle2D.Double(500, 250, 5, 90));
                break;
            case 5:
                g.setColor(new Color(255, 0, 0));
                g.fillOval(70, 40, 50, 50);
                g1.fill(new Rectangle2D.Double(440, 450, 60, 5));
                g1.fill(new Rectangle2D.Double(350, 240, 60, 5));
                g1.fill(new Rectangle2D.Double(345, 360, 5, 80));
                g1.fill(new Rectangle2D.Double(500, 250, 5, 90));
                break;
}