Can't see components

Question

The desired effect is to draw a red and a blue square. The squares don't show up on the panel. Resolution?
Thanks!
/* File RBSquarePanel.java */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class RBSquarePanel extends JPanel implements MouseListener,
        MouseMotionListener {
        private int startX, startY;
        private int prevX, prevY;
        private boolean dragging;
        private int theSquare = 0; // +1: Red square;
                                   // -1: Blue square;
                                   //  0: Not in clickable region.
        // Draw red and blue squares on-screen.
        public class Square extends JPanel {
                protected int x;
                protected int y;
                protected Color c;
                public Square() {
                        this(Color.BLACK, 50, 50);
                        addMouseListener(RBSquarePanel.this);
                        addMouseMotionListener(RBSquarePanel.this);
                public Square(Color c, int x, int y) {
                        addMouseListener(RBSquarePanel.this);
                        addMouseMotionListener(RBSquarePanel.this);
                public void paintComponent(Graphics g) {
                         // Create a square 50 pixels on a side
                         // with color c and anchor point (x, y).
                         super.paintComponent(g);
                         c = Color.BLUE;
                         g.setColor(c);
                         g.fillRect(x, y, 50, 50);
// etc.
        }  // End class Square
        public RBSquarePanel() {
                setBackground(Color.BLACK);
                Square redSquare  = new Square(Color.RED, 50, 50);
                Square blueSquare = new Square(Color.BLUE, 150, 150);
                addMouseListener(this);
                addMouseMotionListener(this);
} // End class RBSquarePanel
/* File RBSquare.java */
import javax.swing.JFrame;
* A stand-alone application that opens a window containing an
* RBSquarePanel
public class RBSquare {
   public static void main(String[] args) {
         JFrame window = new JFrame("RBSquare");
         RBSquarePanel content = new RBSquarePanel();
         window.setContentPane(content);
         window.setSize(350, 350);
         window.setLocation(10,10);
         window.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
         window.setVisible(true);
} // End class RBSquare

Answer 1

t-t wrote:
Is it not enough to instantiate `redSquare' and `blueSquare' within `RBSquarePanel' and create an RBSquarePanel object later?Your program's lack function partially demonstrates the answer to this question better than I can. Now if you add the redSquare and blueSquare JPanels onto the main JPanel, and play with your code a little bit, you'll be able to fully answer this question yourself. You serioulsy need to go over the Sun Swing tutorials before you try to do more Swing coding.