java控制图片显示时序问题

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图片显示，屏幕上有两张图片，一张显示正常图片，一张显示提示图片。
循环更换图片，假定一次播放时间为80ms，
1.正常图片与提示图片同时显示
2.正常图片显示80ms
3.提示图片显示前20ms，后60ms不显示
下列代码以颜色代替图片，我该如何控制提示图片，提示图片显示不稳定

import javax.swing.*;
import java.awt.*;

/**
 * @className: JFrameTest
 * @description: 正常图片与提示图片同时显示，一次图片更换时间 80ms，
 *               正常图片显示80ms，提示图片显示前20ms，剩余60ms不显示，
 *
 * @version: 1.0
 **/
public class JFrameTest extends JFrame{

    private JPanel normalPane;  //正常图片
    private JLabel colorPane;   //提示图片

    public JFrameTest(){
        normalPane = new JPanel();
        normalPane.setBackground(Color.WHITE);
        normalPane.setPreferredSize(new Dimension(100,100));
        normalPane.setMaximumSize(new Dimension(100,100));
        colorPane = new JLabel();
        colorPane.setBackground(Color.WHITE);
        colorPane.setPreferredSize(new Dimension(100,100));
        colorPane.setMaximumSize(new Dimension(100,100));

        JPanel contentPane = new JPanel();
        contentPane.setPreferredSize(new Dimension(400,400));
        contentPane.setBackground(Color.BLACK);
        contentPane.setLayout(new BorderLayout());
        setContentPane(contentPane);

        contentPane.add(normalPane,BorderLayout.NORTH);
        contentPane.add(colorPane,BorderLayout.SOUTH);
        setSize(new Dimension(400,400));
        setVisible(true);
    }

    public synchronized void setColorPaneVisible(boolean visible){
        colorPane.setVisible(visible);
    }

    public void setNormalPaneVisible(boolean visible){
        normalPane.setVisible(visible);
    }

    static class Task implements Runnable{

        private JFrameTest jFrameTest;
        private int totalTime;
        private int colorWaitTime;
        public Task(JFrameTest jFrameTest,int totalTime,int colorWaitTime){
            this.jFrameTest = jFrameTest;
            this.totalTime = totalTime;
            this.colorWaitTime = colorWaitTime;
        }
        @Override
        public void run() {
            while (true){
                try{
                    jFrameTest.setNormalPaneVisible(true); //模拟更换图片
                    jFrameTest.setColorPaneVisible(true);
                    Thread.sleep(colorWaitTime);
                    jFrameTest.setColorPaneVisible(false);
                    Thread.sleep(totalTime-colorWaitTime);
                }catch (Exception e){e.printStackTrace();}
            }
        }

    }

    public static void main(String[] args) {
        JFrameTest jFrameTest = new JFrameTest();
        int totalTime = 80;   //总体轮询时间
        int colorWaitTime = 20; //提示图片显示时间
        new Thread(new Task(jFrameTest,totalTime,colorWaitTime)).start();

    }
}