ScripterRon, rather than use JNI you could look at JNA. It will let you eliminate all the C code from your project and just call into the library with a regular Java interface. It's much more convenient.
Thanks, Mike. I did look at JNA but I decided to stay with JNI since the interface stub is only a couple of lines of C code and I didn't want to add another dependency to my project. I was already familiar with JNI (I just finished writing native hash routines for a Nxt project).