Is it possible to integrate Voice Over IP (VOIP)?
The answer is simple: absolutely! In fact, lots of technology can be integrated with RCP.
The Eclipse Communication Framework (ECF) project is currently working on providing support for VOIP. In the meantime, if you are aware of an alternative solution that lets you leverage VOIP from Java, you can use it as part of your RCP application. Eclipse RCP will supply the desktop integration, window management, component model, extensibility, update manager, etc.; your VOIP library supplies the VOIP support.