这是我写的一个关于Timer的程序，要求0.5秒变换一次直线的颜色，调试通过了，但在运行中总是出错，各位大大帮忙看看！！谢谢了！
//===============E1103.java===============
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
class E1103 extends JFrame
{
    private int count=1;
    private Color color ;
    private Graphics g;
    private Font font;
    public E1103()
    {
        super("E1003");
        
        setSize(400,180);
        setVisible(true);
    }
    public void paint(Graphics s)
    {        
            
                
        ActionListener task = new ActionListener()
        {
            public void actionPerformed(ActionEvent evt)
            {
                font = new Font("Serif",Font.BOLD,20);
                
                switch (count%3)
                {
                    case 1: color= Color.red; break;
                    case 2: color= Color.green; break;
                    default: color= Color.blue;        
                }
                g.setFont(new Font("Serif",Font.BOLD,20));
                g.setColor(color);
                g.drawString("按顺序变换水平线为红绿蓝色",60,100);        
                g.drawLine(60,150,320,150);
                g.drawLine(70,154,330,154);
                g.drawLine(80,158,340,158);
                count++;
            }
        };
        Timer time = new Timer(500, task);
        time.start();
        
    }
    public static void main(String[] args)
    {
        E1103 app = new E1103();
        app.addWindowListener(new MyWindowListener());
    }
}

冰封大大不在吗？帮忙看看吧！我琢磨得头都晕了！

还是没有人回答吗？现在各位大大都不在了吗？