Wondering how to interface Arduino with Java

Hi all,

So I have an idea for an Arduino project, and what I'd like to do is pull analogue sensor data from my Arduino (I'm thinking of using the UNO) and use that data in a Java front end GUI. I can build the GUI using Swing without any issues, but I'm not sure how to interface the Arduino in Java so the data the Arduino is reading can be used by my program. I have seen a few posts dealing with using the RXTX library in Java and reconfiguring JAR files, but nothing really definitive on how to work with the data coming from an Arduino. I assume there must be a way to pull data from the serial port once the Arduino is plugged in, but I am totally clueless as to how this would work. I'm going to have several streams of data (from several pressure sensors) so I need to know how to get each stream's data separately from the USB port. It'd also be great to do this (get the data from the Arduino to my Java program) via wifi too if possible, so if that's something you are familiar with, or if you can tell me where to look to find out how to do it, I'm all ears!

Thanks in advance for any and all help you can offer, and any of this needs clarification, please feel free to ask me to elaborate.

Why not start with Processing, and take it from there?