There is a project called JACOB which allows you to call  COM from
Java. The main website is http://danadler.com/jacob/ . There isn't
much documentation on it just some examples from what I've found.
There's a yahoo group called jacob-project that may be helpful. I've
used Jacob to do some pretty neat things in MS Word from Java, it's a
pretty nice tool.

Myself, I would use JNI, and write my own C++ and Makefiles and
everything, and call  COM from there, but there's also:

http://www.jintegra.com
which leads to
http://www.intrinsyc.com/products/j-integra/

Another option is simply not to call com  at all, and implement it all
in Java.