New to Java, Creating screens with swings on Mac OS X

[mo_mughrabi]

Hi,
am totally new to the forum and Java itself. I bought a book to teach me how to write Java programs from beginning.. The book has a CD attached with it, everything seem to be working fine accept when I try to create classes that contain javax.swing.JPanel.. look at the code below I couldn't run this on Mac OS X.. is there something am missing or should I download some library files in order for this class to run?

import java.awt.Graphics;
import javax.swing.JPanel;

public class Shapes extends JPanel
{
   private int choice; // user's choice of which shape to draw
   
   // constructor sets the user's choice
   public Shapes( int userChoice )
   {
      choice = userChoice;
   } // end Shapes constructor
   
   // draws a cascade of shapes starting from the top-left corner
   public void paintComponent( Graphics g )
   {
      super.paintComponent( g );
      
      for ( int i = 0; i < 10; i++ )
      {
         // pick the shape based on the user's choice
         switch ( choice )
         {
            case 1: // draw rectangles
               g.drawRect( 10 + i * 10, 10 + i * 10, 
                  50 + i * 10, 50 + i * 10 );
               break;
            case 2: // draw ovals
               g.drawOval( 10 + i * 10, 10 + i * 10, 
                  50 + i * 10, 50 + i * 10 );
               break;
         } // end switch
      } // end for
   } // end method paintComponent
} // end class Shapes