我正在尝试创建一个gui，在这个gui中，我可以根据applet中的内容在applet的“上方”绘制一个applet。为了测试这一点，我尝试通过使用jlayeredpane创建一个填充背景的面板来填充一个简单的矩形。不管我怎么试，我都不能让它工作。

import java.applet.Applet;
import java.awt.Color;
import java.awt.GridLayout;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;

public class GUI {

private static JFrame frame;
private static JLayeredPane layers;
private static JPanel panel;
private static Applet applet;
private static final String JAR_PATH = "file:C:/Applet.jar";

public static void main(String args[]) throws MalformedURLException, ClassNotFoundException, InstantiationException, IllegalAccessException{
    ClassLoader clientClassLoader = new URLClassLoader(new URL[]{new URL(JAR_PATH)});
    Class<?> client = clientClassLoader.loadClass("Loader");
    frame = new JFrame("JLayeredPane Testing");
    frame.setSize(400, 400);
    frame.setResizable(false);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLayout(new GridLayout());
    applet = (Applet) client.newInstance();
    layers = new JLayeredPane();
    panel = new JPanel();
    panel.setSize(200, 200);
    panel.setOpaque(true);
    panel.setBackground(Color.BLACK);
    layers.add(panel, JLayeredPane.PALETTE_LAYER);
    layers.add(applet, JLayeredPane.DRAG_LAYER);
    frame.setContentPane(layers);
    frame.setVisible(true);
    applet.init();
}

}

运行程序时小程序不显示或初始化。