Useful links for the JOGI API
OpenGroupware.org - the software that started it all.
Opengroupware.org XML-RPC manual - required reading for anyone that wants to know whats going on behind the scenes of JOGI.
XML-RPC - the home of XML-RPC
Apache XML-RPC implementation - the Apache XML-RPC library; JOGI comes with an adapter for this library.
Eclipse - the IDE that made JOGI possible. If you are a Java programmer, get Eclipse, Period. Eclipse will at least double your productivity, help you produce more stable code and give your cat a shiny coat (or let your tomatoes grow bigger, if you're into gardening). Oh, and if you don't like IDEs and have a bumper sticker that says something along the lines of "You'll have to pry my VIM out of my cold, dead fingers", STILL try Eclipse. Both developers of this project were hardcore VIM users before Eclipse but haven't written one line of Java code in VIM after a couple of hours alone with Eclipse (and are currently looking for a VA (VIM-users Anonymous) group in our vicinity to help us get rid of the occasional ":w" in our source files).