Sample WebRTC signaling server implementation (Android client side)
Server side: https://github.com/nkming2/webrtc-signaling-server
Client side for browser: https://github.com/nkming2/webrtc-signaling-client

Dependency

• socket.io-client-java
• WebRTC native library and JNI
  • See: https://webrtc.org/native-code/android