Adding Graphics to Jpanel

Hi again,
I just wondering how I can add a Graphics object like rectangle to a
JPanel?
I have following classes and I can add the Label object into MyPanel
but I cant add drawing object (MyRect) into Jpanel.I know that I am
not constructing any thing in MyRect() constructor! so it make sence
for me that nothing will happen in MyPanel when I call for MyRect
constructor but I don't' know how to call the paintComponent with it's
parameters in MyPanel class!
Could you please let me know is it possible to add a drawing into a
panel?
so what's wrong with this code?

# package MyPack;
# import java.awt.Color;
# import java.awt.Graphics;
# import javax.swing.JPanel;
#
# public class MyRect extends JPanel {
#
# public void paintComponent(Graphics g) {
# g.setColor (Color.BLUE);
# g.drawRect (100, 100, 200, 200);
# =======================
# package MyPack;
# import java.awt.Color;
# import javax.swing.JPanel;
#
# public class MyPanel extends JPanel {
#
# MyPanel() {
# setBackground(Color.green);
# // Add Drawing to Jpanel
# MyRect mrect = new MyRect();
# this.add(mrect);
# // Add Component to Jpanel
# MyLabel mlabel = new MyLabel();
# this.add(mlabel);
# }
# }
# =======================
# package MyPack;
#
# import java.awt.Color;
# import java.awt.Font;
# import javax.swing.JLabel;
#
# public class MyLabel extends JLabel{
# public MyLabel() {
# super("Hello, World!");
# setFont(new Font(null, Font.BOLD, 40));
# setForeground(Color.red);
# }
# }
# =======================
# package mypaneltest;
# import javax.swing.JFrame;
#
# public class MyFrame extends JFrame {
# public MyFrame(){
# super("Test");
# setSize(300,200);
# setLocationRelativeTo(null);
# MyPanel pane = new MyPanel();
# add(pane);
# }
# }
# ======================
# package MyPack;
#
# public class Main {
# public static void main(String[] args) {
# new MyFrame().setVisible(true);
# }
# }