Intermittent problem with ImageIO reading BMP: Empty Region

Question

I am using imageIO to read in a bmp file, like this:
      ImageInputStream is = ImageIO.createImageInputStream(imgURL.openStream());
      Iterator<ImageReader> rdrs = ImageIO.getImageReaders(is);
      if (rdrs.hasNext()) {
        ImageReader r = rdrs.next();
        r.setInput(is);
        result = r.read(0);
      }(I use the same code to read in a whole bunch of images of various kinds.) In development, I got an empty image, so I added a wait:
MediaTracker mt = new MediaTracker(new MyObserver());
    mt.addImage(iconImage, 0);
    try {
      mt.waitForID(0);
    } catch (InterruptedException e) {
    }which seemed to work fine. Except that sometimes, not always, I got a crash:
java.lang.IllegalArgumentException: Empty region!
     at javax.imageio.ImageReader.computeRegions(Unknown Source)
     at com.sun.imageio.plugins.wbmp.WBMPImageReader.read(Unknown Source)
     at javax.imageio.ImageReader.read(Unknown Source)I got that sometimes in development, but once I produced the production version it started happening all the time!
Anyone have an idea what's going on??

Answer 1

That was very close to correct. It seems that the WBMP reader mucks up the input stream before the .ico reader can get to it. The .ico plugin, which is available at [http://www.vdburgh.net/2/f/files/ICOReader/ ] puts out a very nice error message to that effect and suggest using a fresh input stream. So this:
      ImageInputStream is = ImageIO.createImageInputStream(imgURL.openStream());
      Iterator<ImageReader> rdrs = ImageIO.getImageReaders(is);
      while (rdrs.hasNext()) {
        ImageReader r = rdrs.next();
        try {
          r.setInput(is);
          result = r.read(0);
          return result;
        } catch (IllegalArgumentException e) {
          System.out.printf("Bad Image:%s%n", e.getMessage());
          is = ImageIO.createImageInputStream(imgURL.openStream());
      }Does the trick! (So far :)