An OpenID Connect reference implementation in Java on the Spring platform.
High-quality WebSocket client implementation in Java.
Offers very simple and easy-to-use Java classes for Client-Server-Client or just Server-Client applications doing all the work for connection setup, reconnection, timeout, keep-alive, etc. in the background.
XMPP Connection Server for FCM
Java client for NATS
A Complete Fast Android Networking Library that also supports HTTP/2
XMPP Connection Server for FCM using the latest version of the Smack library (4.3.1) + Connection Draining Implementation