I wrote a class that is suppose to draw a red rectangle in a JPanel with and the background of the panel is suppose to be black here is my code


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

public class View extends JFrame
{
private JPanel panel = new JPanel();
public void paint(Graphics g)
{
g.setColor(Color.RED);
g.drawRect(20, 50, 100, 100);
}
public View()
{
setSize(640, 480);
setResizable(true);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setBackground(Color.BLACK);
panel.setSize(640, 480);
panel.setBackground(Color.BLACK);
panel.paint(null);
this.add(panel);
}

public static void main(String[] args)
{
View view = new View();



}
}

and here is what I get as a result there appears to be some glitch in the background

[attachment=7844:WTF.PNG]
(this is a screen of the gui from my code not a minimized Eclipse)

and here is how it is without the paint method it does as it suppose to making a window with a black background

[attachment=7845:without paint method.PNG]


Is it something wrong with my code that it does like that or there is something wrong with my computer ?