Content OF Panel Is Not Visible. Need Help

Question

Hi Guys,
Can someone tell me why the contents of the "VisPanel" (JPanel) class is not showing up in the main window. I just don't understand why it is not visible after i add it to the main window.
Here is the code. You can test it. Only the button shows up. The contents of "VisPanel" class is not visible.
Replace the images in the "VisPanel" class with any image of your choice. I made them 130 X 130. I would have like to add the images in the post but i don't think it is possible to add images to post in this forum.
public class TilesImage extends JFrame{
     private static final long serialVersionUID = 1L;
     public TilesImage(){
            this.setLayout(new GridLayout(2,1));
            this.setSize(600,600);
            this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            VisPanel vis = new VisPanel();
            JPanel pana = new JPanel();
            pana.add(vis);
            BufferedImage sub = vis.getImg().getSubimage(261, 260, 129, 129);
           JButton but = new JButton(new ImageIcon(sub));
           pana.add(but);
           this.add(pana);
           this.setContentPane(pana);
           this.setVisible(true);
           repaint();
       public static void main( String[] args ) {
             new TilesImage();
             //new VisPanel();
class VisPanel extends JPanel{
      private static final int IMAGE_TYPE = BufferedImage.TYPE_INT_ARGB;
       private BufferedImage img;
      public VisPanel() {
             // here you should create a compatible BufferedImage
             //img = new BufferedImage( 450, 350, IMAGE_TYPE ); 
             img = new BufferedImage( 525, 500, IMAGE_TYPE );
                 this.setSize(img.getWidth(), img.getHeight());    
             final int NB_TILES = 4;
             BufferedImage[] tiles = new BufferedImage[NB_TILES];
             tiles[0] = createHorizontalRail( new Color( 255, 255, 255 ) );
             tiles[1] = createVerticalRail( new Color( 255, 255, 255 ) );
             tiles[2] = createCrossing( new Color( 255,   0, 255 ) );
             final int[][] map = new int[][] {
                         {4, 4, 1},    
                           {4, 4, 1},
                           {0, 0, 2},
                           {4, 4, 4}, 
             for (int i = 0; i < map[0].length; i++) {
                   BufferedImage tile = null;
                 for (int j = 0; j < map.length; j++) {
                      if(map[j] == 0){
               tile = tiles[0];
               for (int x = 0; x < tile.getWidth(); x++) {
          for (int y = 0; y < tile.getHeight(); y++) {
          img.setRGB( x + i * 130, y + j * 130, tile.getRGB(x,y) );
               //img.setRGB( x + i * 45, y + j * 32, tile.getRGB(x,y) );
          } if(map[j][i] == 1){
               tile = tiles[1];
               for (int x = 0; x < tile.getWidth(); x++) {
          for (int y = 0; y < tile.getHeight(); y++) {
          img.setRGB( x + i * 130, y + j * 130, tile.getRGB(x,y) );
          if(map[j][i] == 2){
               tile = tiles[2];
               for (int x = 0; x < tile.getWidth(); x++) {
          for (int y = 0; y < tile.getHeight(); y++) {
          img.setRGB( x + i * 130, y + j * 130, tile.getRGB(x,y) );
     this.setVisible( true );
     private BufferedImage createHorizontalRail( final Color c ) {
     final Random r = new Random();
     BufferedImage img = null;
     try {
     img = ImageIO.read(new File("images/crossingsHorizontal.JPG"));
     } catch (IOException e) {
     return img;
     private BufferedImage createVerticalRail( final Color c ) {
     final Random r = new Random();
     BufferedImage img = null;
     try {
     img = ImageIO.read(new File("images/crossingsVertical2.JPG"));
     } catch (IOException e) {
     return img;
     private BufferedImage createCrossing( final Color c ) {
     final Random r = new Random();
     BufferedImage img = null;
     try {
     img = ImageIO.read(new File("images/railCrossing2.JPG"));
     } catch (IOException e) {
     return img;
     public void paintComponent(Graphics g) {
     g.drawImage(img, 0, 0, null);
          public BufferedImage getImg() {
               return img;
          public void setImg(BufferedImage img) {
               this.img = img;
Thanks for your help.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

kap wrote:
The "pana" panel must contain both the contents of the "VisPanel" panel and the button i created. So it is correct to set the contenPane to the "pana" panel. I tried to set the content pane to the "VisPanel" panel. It is visible but the button i added to the "pana" panel cannot be visible.
I hope you understand what i mean here.He understands exactly what you mean and has pointed out your mistake and offered a decent solution. I suggest you take his advice and set the layout of pana not the JFrame.