Incorrect grayscale color on 8 bit graphics devices

There are certain cases in Java in which the setColor command
does not yield a grayscale color when a grayscale color has been
requested. The error only occurs on 8 bit graphics devices and
is particularly prevalent on the Java terminal (Mr Coffee). The
requested color is correct on 24 bit devices. Examination under
the debugger shows the requested color information to be correct.

Although on 8 bit devices, Java returns the "closest match" for
the requested color, my understanding is that when r,g,b all have
the same value, Java guarantees that it will return one of it's grayscale
values. This doesn't seem to be the case in the Java applet below.
The following applet displays a shaded disk that will have an incorrect
color (usually either a red or yellow) for one of the shades of gray when
run on a 8 bit graphics device. And like I said, the r, g, b values are
all the same (according to getRed, getGreen, getBlue).

The applet can be executed as:

     http://deadbolt.east/color_bug/Viewer.html

Note that mouse drag operations will rotate the image.

The source code is at:

    /net/deadbolt.east/usr2/color_bug/Viewer.html
                                      Viewer.java
                                      Model.java
                                      Matrix.java
                                      cube.wrl
                                      disk.wrl
                                      hughes.wrl
                                      sub.wrl
                                      klingon.wrl
                                      

The setColor command is in the Model.java file in a method called render().
The color array is defined in the Model method "set_fg_color".