We thought that it might be useful to show how our Raspberry Pi demo is done, so here are the sources.
As stated in previous posts, the java hardware communications are made using Pi4j library.
Most of the classes are the same as in SampleConsoleServer (sample that comes with the SDK packages). Note that depending on your SDK version the classes might not compile directly (as this was done with our SDK 2.0 beta, but they should be almost the same; if they do not compile for some reason, copy them from your SDK package). The WeatherStation.java contains the IO side of the server and WeatherStationServer.java contains the UA side.