Why is java2d included?

I just downloaded the VisAD jar file and unpacked it.  Everything seems
to be fine except there was an extra 'java2d' directory of files
included in the package.  Does anyone know why it was included?  It
doesn't compile properly because many of the 'java2d' classes its
searching for are missing.  Does anyone know if any of the examples rely
on these classes?  Will I be able to use VisAD properly without these
classes?