Synthetic VoIP using Java

How might I 开发者_运维问答generate synthetic VoIP calls, for testing, using Java?

Are there any open source packages that handle this?

Here is a lot of SIP implementations in Java

http://www.voip-info.org/wiki/view/Open+Source+VOIP+Software

The Festival Speech Synthesis system is really cool: http://en.wikipedia.org/wiki/Festival_Speech_Synthesis_System

It itself is native code, but it's available for all the major platforms and there are Java access wrappers there as well. Very sophisticated and sounds excellent IMO.