JPanel hiden behind JFrame decoration

Question

Hi, I have a JFrame and a JPanel.
The JPanel is going to be double buffered with my own code(active rendering) and will consume the whole JFrame. I want to add other panels later on top of the JPanel. and a pop up menu aswell. So I create a buffer graphic, paint on it and show it on the JPanel.
When I set the JPanel as contentPane or add it in the center then a part of the Panel is hiden by the frame decorations. How can I force the Jpanel to display totaly, without a part being hiden.
I know one solution: create a top cst make it 30 pixels and everytime i paint add it to the y var. But then again... that isn't a 'real' solution.
I would like to be 0,0 the left top of my Jpanel and not 0,0 hiden behind the decoration...
So when I typ contentPane.setLayout(new FlowLayout(FlowLayout.CENTER)); then I would like to see the button i would add.
    pauseButton = new JButton("pause");
    pauseButton.setIgnoreRepaint(true);
    // Create the space where the play/pause buttons go.
    playButtonSpace = new JPanel(new BorderLayout());
    playButtonSpace.setOpaque(false);
    playButtonSpace.add(pauseButton);
    contentPane.add(playButtonSpace);Now I can see a small part of the button the rest is hiden behind the frame decoration.
public test() {
    gamePanel = new JPanel();
    gamePanel.setPreferredSize(new Dimension(500, 600));
    gamePanel.setMinimumSize(new Dimension(500, 600));
    gamePanel.setMaximumSize(new Dimension(500, 600));
    JFrame frame = new JFrame("Hello world!");
    frame.setContentPane(gamePanel);
    frame.pack();
    frame.setResizable(false);
    frame.setVisible(true);
    Graphics g = frame.getGraphics();          // quick test
    g.drawString("can you see me1?", 0, 0);
    g.drawString("can you see me2?", 0, 20);
    g.drawString("can you see me3?", 0, 50);
  public static void main(String[] args) {
    new test();
}can you see me3 is visible the rest is not.
I use:
frame.getLayeredPane().paintComponents(g);to do my custom painting.
How do i show the panel completely?

Answer 1

Usually we draw overriding the method "paintComponent":
* Test.java
import java.awt.*;
import javax.swing.*;
class Test {
    public Test() {
        JPanel gamePanel = new JPanel() {
            protected void paintComponent(final Graphics g) {
                super.paintComponent(g);
                int h = g.getFontMetrics().getHeight();
                for (int row = 1; row < 10; row++) {
                    g.drawString("can you see me" + row + "?", 0, row * h);
        JFrame frame = new JFrame();
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(gamePanel, BorderLayout.CENTER);
        frame.setVisible(true);
    public static void main(final String[] args) {
        new Test();
}