怎么用双缓冲解决java中关于Applet程序让图片动起来后如何解决屏闪

package yb_8_115;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class JSG extends Frame {
// 定义游戏关数0代表开始1代表第一关。。。
int state = 0;
// 定义全局变量用于拿到图片系统路径
// 得到默认工具包
Toolkit tk = Toolkit.getDefaultToolkit();
// 通过工具包拿到图片
Image start = tk.getImage(
// 拿路径
JSG.class.getResource("/image/start.png"));
Image bj2 = tk.getImage(JSG.class.getResource("/image/bj_2.png"));
Image dyg = tk.getImage(JSG.class.getResource("/image/lesson_1.png"));
Image heart = tk.getImage(JSG.class.getResource("/image/heart.png"));
Image songshu = tk.getImage(JSG.class.getResource("/image/songshu.png"));