Java and dlls

Is it possible to use an existing dll with java?
If so what 800+ pages book do one need to memorize
to accomplish this?
Any hint will be most appreciated

Yes.
Take a look:
http://java.sun.com/docs/books/tutorial/native1.1/stepbystep/index.html

Thank you for the fast response.
I will check that one out. It has to be good
because it contains the word "tutorial" which sits
very well right now.