byte[] quantizationTableData = segmentReader.readSegment(JpegSegmentReader.SEGMENT_MARKER_DQT);
byte[] quantizationTableData = segmentReader.readSegment(JpegSegmentReader.SEGMENT_DQT);
    public void testReadDQTSegment() throws Exception    {        File jpeg = new File("src/com/drew/imaging/exif/test/withExif.jpg");        JpegSegmentReader segmentReader = new JpegSegmentReader(jpeg);        byte[] quantizationTableData = segmentReader.readSegment(JpegSegmentReader.SEGMENT_MARKER_DQT);        assertTrue("shouldn't have zero length quantizationTableData", quantizationTableData.length > 0);        assertTrue("quantizationTableData shouldn't start with 'Exif'", !"Exif".equals(new String(quantizationTableData, 0, 4)));    }