This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
Hardware interfacing will require that you connect your java code to hardware specific code written in some other language using JNI. For communicating with serial and parallel ports you can use the COMM API that includes hardware specific routines for some architectures. Bill