The PNOZmulti Configurator is an established multi-language product being developed for more than 10 years here in our Irish office.
It is developed using Java in Eclipse with SWT/JFace for the UI; an efficient inheritance model for the middle tier and a combination of byte stream, XML and EMF for data persistence.
The Configurator communicates to hardware using COM ports, Ethernet and USB ports. The team are constantly adding new features taking these through the full Development Life Cycle as well as updating existing functionality.
A developer could be implementing the Observer pattern in UI one day; deciphering byte streams from the hardware another day and writing JUnits the next. There is a large suite of automated tests and aspectj classes run on a regular basis to maintain the high quality software and safety architecture.