Border / paint and update problem

Question

Hi,
I have written a simple GUI and have two problems:
first, a white border is being displayed a the right, left and bottom side.
Second: for testing purposes I am drawing a simple rectangle; I am starting at (1, 1) but it's actually being drawn maybe at (-5, -5). Sometimes it's not being drawn at all.
Here is my code:
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.WindowConstants;
public class MainWindow extends JFrame {
     private static final long serialVersionUID = 1L;
     private JPanel jPanel1;
     final static BasicStroke stroke = new BasicStroke(2.0f);
     public MainWindow() {
          initComponents();
     private void initComponents() {
          jPanel1 = new JPanel();
          setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
          jPanel1.setBackground(new Color(153, 204, 255));
          jPanel1.setPreferredSize(new Dimension(1024, 768));
          getContentPane().add(jPanel1);
          pack();
     public void paint(Graphics g){
          update(g);
     public void update(Graphics g){
          Graphics2D g2 = (Graphics2D)g;
          g2.setStroke(stroke);
          g2.draw(new Rectangle2D.Double(1, 1, 50, 50));
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new MainWindow().setVisible(true);
}I am not sure about the paint / update method. I read the Swing tutorial and found examples where the drawing is being done in the update method... Does this have certain advantages?
Thanks for your help!

Answer 1

I still don't have it... where is my mistake?
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class MainWindow extends JPanel {
     private static final long serialVersionUID = 1L;
     public MainWindow() {
          initComponents();
     private void initComponents() {
          JComponent face = new InitMainWindow();
          face.setPreferredSize( new Dimension(250, 250) );
          JFrame frame = new JFrame();
                frame.setTitle("Test");
          frame.setBackground(new Color(153, 204, 255));
          frame.addMouseListener(new MouseAdapter() {
               public void mouseClicked(MouseEvent evt) {
                    mouseClick(evt);
          frame.pack();
          frame.setVisible( true );
     private void mouseClick(MouseEvent evt) {
          System.out.println("Click!");
     protected void paintComponent(Graphics g) {
          super.paintComponent(g);
          g.setColor(Color.BLACK);
          g.drawLine(100, 100, 150, 150);
     public static void main(String args[]) {
          java.awt.EventQueue.invokeLater(new Runnable() {
               public void run() {
                    new MainWindow().setVisible(true);
}