JPanel

package cn.rushangw.lesson05;

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

public class JPanelDemo extends JFrame {
    public JPanelDemo() {

        Container container = getContentPane();

        container.setLayout(new GridLayout(2,1,10,10));

        JPanel panel = new JPanel(new GridLayout(1,3));

        container.add(panel);

        panel.add(new JButton("1"));
        panel.add(new JButton("1"));
        panel.add(new JButton("1"));

        setVisible(true);
        setBounds(1,1,500,500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }

    public static void main(String[] args) {
        new JPanelDemo();
    }
}