Thread: Code wont run. I know there is no main class, but this is from a book. Is it wrong??

import java.awt.*;

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

public class ColorPanel extends JPanel{

public ColorPanel(Color backColor)
{
setBackground(backColor);

}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.blue);
g.drawRect(10, 5, 120, 20);
g.setColor(Color.red);
g.drawString("Hello", 20, 20);


}
}

u must add something like this:

 
public class Main {
    public static void main(String[] args) {
        final JFrame fr = new JFrame();
        JPanel pan = new ColorPanel(Color.black);
        fr.add(pan);
        SwingUtilities.invokeLater(new Runnable() {
 
            public void run() {
                fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                fr.setSize(200, 200);
                fr.setVisible(true);
            }
        });
    }
}

Also, I think paintComponent() is a protected method of JPanel.

Yep. I checked to make sure and it is, though it's not a JPanel method directly. It's a JComponent method that JPanel inherited.