The missing bridge between Java and native C++
Jitsi is an audio/video and chat communicator that supports protocols
Java VoIP Softphone (SIP) (replaced by jfPhone)
Accent interfaces and controls systems through goals and policies
Enterprise telephony recording and retrieval system
SIP Video Multiconference Media Server with WebRTC support.
Java VoIP/SIP PBX system (replaced by jfPBX)
Capture and display SIP and DIAMETER messages
SIP2 Library for Java.
Open source streamlined SIP client built on Linphone
A suite of open-source tools and frameworks for creating SIP apps