GUI 5: separate panels combined, two examples

Calculator shape (JLabel and JTextField, JButton, JLabel and JTextField)

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

public class Main extends JFrame
{
	public Main()
	{
		setTitle("Ten Color Buttons Frame");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		Container c = getContentPane();
		c.setLayout(new GridLayout(3, 1));
		
		JPanel p = new JPanel();
		p.setBackground(Color.GRAY);
		p.setLayout(new FlowLayout());
		p.add(new JLabel("수식입력"));
		p.add(new JTextField(""));
		
		JPanel pan = new JPanel();
		pan.setBackground(Color.YELLOW);
		pan.setLayout(new FlowLayout());
		pan.add(new JLabel("계산결과"));
		pan.add(new JTextField(""));
		
		JPanel pa = new JPanel();
		pa.setLayout(new GridLayout(4,3));
		JButton z = new JButton("0");
		pa.add(z);
		String[] str = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "CE", "계산", "+", "-", "x", "/"};
		for(int i = 0; i < 11; i++)
		{
			pa.add(new JButton(str[i]));			
		}
		for(int i = 0; i < 4; i++)
		{
			JButton y = new JButton(str[11+i]);
			y.setBackground(Color.CYAN);
			pa.add(y);
		}

		c.add(p);
		c.add(pa);
		c.add(pan);
		
		setSize(700,500);
		setVisible(true);
	}

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

JButton, null layout, JLabel and JTextField

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

public class Main extends JFrame
{
	public Main()
	{
		setTitle("여러 개의 패널을 가진 프레임");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		Container c = getContentPane();
		c.setLayout(new GridLayout(3,1))
		
		JPanel one = new JPanel();
		one.setLayout(new FlowLayout());
		one.setBackground(Color.GRAY);
		one.add(new JButton("열기"));
		one.add(new JButton("닫기"));
		one.add(new JButton("나가기"));
	
		JPanel two = new JPanel();
		two.setLayout(null);
		for(int i = 0; i < 10; i++)
		{
			JLabel hi = new JLabel("*");
			hi.setForeground(Color.RED);
			hi.setSize(10, 10);
			hi.setLocation((int)(Math.random()*300) + 100, (int)(Math.random()*300) + 100);
			two.add(hi);
		}
		
		JPanel three = new JPanel();
		three.setLayout(new FlowLayout());
		three.setBackground(Color.YELLOW);
		three.add(new JLabel("Word Input"));
		three.add(new JTextField("                   "));
		
		c.add(one);
		c.add(two);
		c.add(three);
		
		setSize(1000, 800);
		setVisible(true);
	}
	
	public static void main(String[] args)
	{
		new Main();
	}
}