JPanel en java!

En esta ocasión hablaremos sobre los JPanel en java, en el vídeo explicare como crear el objeto e instanciarlo.

Clase ventana

import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class Ventana extends JFrame{
 
 JPanel pnl_panel;
 JButton btn_1, btn_2, btn_3, btn_4;

 public Ventana() {
  this.setTitle("JPanel en java");
  this.setSize(500,500);
  this.setLocation(450,50);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  this.setVisible(true);
  
  componentes();
 }
 public void componentes(){
  this.setLayout(null);
  add(pnl_panel = new JPanel());
  
  add(btn_1 =new JButton("rojo"));
  btn_1.setBounds(10,10,100,20);
  
  btn_1.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
      pnl_panel.setBackground(Color.red);
    }
  });
  
  add(btn_2 =new JButton("negro"));
  btn_2.setBounds(120,10,100,20);
  btn_2.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
      pnl_panel.setBackground(Color.black);
    
    }
  });
  
  add(btn_3 =new JButton("amarillo"));
  btn_3.setBounds(230,10,100,20);
  btn_3.addActionListener(new ActionListener() {
 
   public void actionPerformed(ActionEvent e) {
     pnl_panel.setBackground(Color.yellow);
    
    }
  });  
  
  add(btn_4 = new JButton("azul"));
  btn_4.setBounds(340,10,100,20);
  btn_4.addActionListener(new ActionListener() {
  
   public void actionPerformed(ActionEvent e) {
     pnl_panel.setBackground(Color.blue);
    
    }
  });
  pnl_panel.setBounds(10,70,480,400);
  pnl_panel.setBorder(BorderFactory.createTitledBorder("Mi panel")); 
 }
}

Clase Main

public class Main {

 public static void main(String[] args) {
    // TODO Auto-generated method stub
    Ventana v = new Ventana();
 }

}

aqui les pongo el codigo también para que lo descarguen si quieren!
codigo en GitHub