Getting a black image after joining two images

Question

Hey Guys,
I have joined two images. In the joined image. i am getting the first image but the second one im getting as a black image. Can you please tell me what is the problem??
Below is the code:
w = inv*img[inv].getWidth(null) + img1.getWidth(null);
     h = Math.max(img[inv].getHeight(null), img1.getHeight(null));
     BufferedImage[] joinedImg = new BufferedImage[lnuInvoiceIndex];
     Graphics2D[] g = new Graphics2D[lnuInvoiceIndex];
JPEGImageEncoder[] encoder=new JPEGImageEncoder[lnuInvoiceIndex];
     for(int join=0;join<=lnuInvoiceIndex;join++){
joinedImg[join]=new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
g[join] = joinedImg[join].createGraphics();
g[join].drawImage((BufferedImage)thumbImage[inv], 0,0, null);
encoder[join] = JPEGCodec.createJPEGEncoder(response.getOutputStream());
encoder[join].encode((BufferedImage)joinedImg[join]);
}

Answer 1

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import javax.swing.*;
public class JoinImages {
    private JPanel getContent(BufferedImage[] images) {
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(wrap(join(images, 4)), "Before");
        panel.add(wrap(join(images, 1)), "Last");
        panel.add(wrap(join(images, 2)));
        return panel;
    private BufferedImage join(BufferedImage[] images, int rows) {
        int cols = images.length/rows;
        // For all images having the same size.
        int iw = images[0].getWidth();
        int ih = images[0].getHeight();
        int w = cols*iw;
        int h = rows*ih;
        int type = BufferedImage.TYPE_INT_RGB;
        BufferedImage image = new BufferedImage(w, h, type);
        Graphics2D g2 = image.createGraphics();
        for(int j = 0, index = 0; j < rows; j++) {
            for(int k = 0; k < cols; k++) {
                int x = k*iw;
                int y = j*ih;
                g2.drawImage(images[index++], x, y, null);
        g2.dispose();
        return image;
    private JLabel wrap(BufferedImage image) {
        return new JLabel(new ImageIcon(image),
                          JLabel.CENTER);
    public static void main(String[] args) throws IOException {
        String[] ids = { "-c---", "--g--", "---h-", "----t" };
        BufferedImage[] images = new BufferedImage[ids.length];
        for(int j = 0; j < images.length; j++) {
            String path = "images/geek/geek" + ids[j] + ".gif";
            images[j] = javax.imageio.ImageIO.read(new File(path));
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new JoinImages().getContent(images));
        f.pack();
        f.setLocation(200,200);
        f.setVisible(true);
}Geek images from [Using Swing Components: Examples|http://java.sun.com/docs/books/tutorial/uiswing/examples/components/index.html].