各位大佬有人能帮我看看这个代码有什么问题吗？

package cn.de.k;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

/**
 * 游戏窗口
 */
import javax.swing.JFrame;

public class WbicCaod  extends JFrame{

    Image nusm=GameUtil.getImage("jvth/nusm.jpg");
    Image jtpw=GameUtil.getImage("jvth/jtpw.jpg");
    //绘制图形
   
    public void paint(Graphics g) {
        
        g.drawImage(nusm, 250,250, null);
        g.drawImage(jtpw, 500, 300, null);
        
    }
    //创建主窗口
    public void launchFrame() {
        this.setTitle("标题");
        this.setVisible(true);//显示窗口
        this.setSize(500,500);//窗口大小
        this.setLocation(300,300);//窗口位置
        this.addWindowListener(new WindowAdapter() {
            
            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
    public static void main(String[] args) {
        WbicCaod a =new WbicCaod();
        a.launchFrame();
    }

}