gst1-java-core:0.9.4 libnice issue
There seems to be a problem in conjunction with gst1-java-core:0.9.4 and the webrtcbin plugin. It is currently not possible to traverse NAT. WebRTC connectivity from within a Java app to another party is only possible, if both are acting in the same network. A detailed attempt to approach the problem is documented here https://github.com/centricular/gstwebrtc-demos/issues/117
Let me know, what additional information you need in order to tackle the issue