Java Tutorial/2D Graphics/ImageReader

Show Image with ImageReader

import java.awt.Graphics;
import java.awt.Panel;
import java.awt.image.BufferedImage;
import java.io.FileInputStream;
import java.util.Iterator;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
import javax.swing.JFrame;
public class Main extends Panel{
  private BufferedImage images[];
  private int imageIndex = 0;
  public Main(String filename) throws Exception{
      FileInputStream fin = new FileInputStream(filename);
      String suffix = filename.substring(filename.lastIndexOf(".") + 1);
      System.out.println("suf " + suffix);
      Iterator readers = ImageIO.getImageReadersBySuffix(suffix);
      ImageReader imageReader = (ImageReader) readers.next();
      ImageInputStream iis = ImageIO.createImageInputStream(fin);
      imageReader.setInput(iis, false);
      int num = imageReader.getNumImages(true);
      images = new BufferedImage[num];
      for (int i = 0; i < num; ++i) {
        images[i] = imageReader.read(i);
      }
      fin.close();
  }
  public void paint(Graphics g) {
    if (images == null)
      return;
    g.drawImage(images[imageIndex], 0, 0, null);
    imageIndex = (imageIndex + 1) % images.length;
  }
  static public void main(String args[]) throws Exception {
    JFrame frame = new JFrame("ShowImageIR.java");
    Panel panel = new Main(args[0]);
    frame.getContentPane().add(panel);
    frame.setSize(400, 400);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}