com.sun.imageio.plugins.jpeg.JPEGImageWriter

The following three methods have the same bug :
    private int getSrcCSType(ColorModel cm)
    private int getDestCSType(ImageTypeSpecifier destType)
    private int getDefaultDestCSType(ColorModel cm)

which is that the switch statement falls through to the next
case (missing break :)
         case ColorSpace.TYPE_3CLR:
                if (cs == JPEG.YCC) {
                    if (alpha) {
                        retval = JPEG.JCS_YCCA;
                    } else {
                        retval = JPEG.JCS_YCC;
                    }
                }
            case ColorSpace.TYPE_CMYK:
                retval = JPEG.JCS_YCCK;
                break;