程序代码：

import java.awt.*;
import javax.swing.*;
public class TestFrame extends JFrame {   
    private Image image =  null ;
    private ImageIcon icon = new ImageIcon("E:\\壁纸\\动漫超赞CG壁纸1920x1200(38P)\\001.jpg");
   public TestFrame(){      
         super("测试窗口");       
    Toolkit toolkit = this.getToolkit();      
    Dimension dimension= toolkit.getDefaultToolkit.getScreenSize();       
    this.setSize(dimension.width,dimension.height);       
    this.setVisible(true);       
    this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);   
   }   
   public static void main(){       
    new TestFrame();   
   }    //绘制背景这个方法jvm会自动调用   
   public void paint(Graphics g){       
    super.paint();       
    image = icon.getImage();       
    g.drawImage(image,0,0,null);   
   } 
}