[求助]这个GUI界面为什么没有显示出正确的结果
我想显式以下的图形，但是没有实现，为什么？

Java code

package justdoit.gui;
import java.awt.*;
public class TestLayout {
    public static void main(String[] args) {
        Panel con_1 = new Panel();
        Panel con_2 = new Panel();
        
        Button b1 = new  Button("BUTTON");
        Button b2 = new  Button("BUTTON");
        con_1.setLayout(new GridLayout(2,1));
        con_1.add(b1);
        con_1.add(b2);
        
        Button b3 = new  Button("BUTTON");
        Button b4 = new  Button("BUTTON");
        Button b5 = new  Button("BUTTON");
        Button b6 = new  Button("BUTTON");
        con_2.setLayout(new GridLayout(2,2));
        con_2.add(b1);
        con_2.add(b2);
        con_2.add(b3);
        con_2.add(b4);
        
        Button b7 = new  Button("BUTTON");
        Button b8 = new  Button("BUTTON");
        Button b9 = new  Button("BUTTON");
        Button b0 = new  Button("BUTTON");
        
        Frame f = new Frame("fourLayout");
        f.setLayout(new GridLayout(2,3));
        f.add(b7);
        f.add(con_1);
        f.add(b8);
        f.add(b7);
        f.add(con_2);
        f.add(b9);
        f.pack();
        f.setSize(400,300);
        f.setVisible(true);
    }
}

------解决方案--------------------
import java.awt.*;
public class TestLayout {
public static void main(String[] args) {
Panel con_1 = new Panel();
Panel con_2 = new Panel();

Button b1 = new Button("BUTTON");
Button b2 = new Button("BUTTON");
con_1.setLayout(new GridLayout(2,1));
con_1.add(b1);
con_1.add(b2);

Button b3 = new Button("BUTTON");
Button b4 = new Button("BUTTON");
Button b5 = new Button("BUTTON");
Button b6 = new Button("BUTTON");
con_2.setLayout(new GridLayout(2,2));
con_2.add(b3);
con_2.add(b4);
con_2.add(b5);
con_2.add(b6);

Button b7 = new Button("BUTTON");
Button b8 = new Button("BUTTON");
Button b9 = new Button("BUTTON");
Button b0 = new Button("BUTTON");

Frame f = new Frame("fourLayout");
f.setLayout(new GridLayout(2,3));
f.add(b7);
f.add(con_1);
f.add(b8);
f.add(b9);
f.add(con_2);
f.add(b0);
f.pack();
f.setSize(400,300);
f.setVisible(true);
}
}
太粗心了