I tried creating images from BLOBs in Northwind database that Microsoft
provides as a sample for its SQL Server 2000. These BLOBs contain BMP
images, but for some weird reason all byte arrays have a 78-byte header
prepended to the contents, so in order to produce the displayable image the
header must stripped off first.

So, I tried this code in JAI:

// Get byte[] data from the BLOB, then do the following:
ByteArraySeekableStream stream = new ByteArraySeekableStream(data, 78,
data.length - 78);
PlanarImage source = JAI.create("stream", stream);
WritableRaster raster = source.copyData();    <== exception thrown here
ColorModel cm = source.getColorModel();
BufferedImage image = new BufferedImage(cm, raster, false, (Hashtable)
null);

It did not work. Then I changed it to this:

// Get byte[] data from the BLOB, then remove the header:
byte[] newData = new byte[data.length - 78];
for (int i = 78; i < newData.length; i++)
   newData[i - 78] = data[i];        // make new byte array, stripping off
first 78 bytes
ByteArraySeekableStream stream = new ByteArraySeekableStream(newData);
PlanarImage source = JAI.create("stream", stream);
WritableRaster raster = source.copyData();    <== no exception anymore
BufferedImage image = new BufferedImage(cm, raster, false, (Hashtable)
null);

Everything worked.

So, it appears to me that ByteArraySeekableStream does not handle the offset
properly in its constructor. I haven't found any bug reports or a discussion
of this matter on Forums.

Did anyone run into something similar? If not, I will file a bug report with
Sun.

TIA for any enlightenment.

Alex Molochnikov
Gestalt Corporation
www.gestalt.com