JSR 356: Java API for WebSocket
A barebones WebSocket client and server implementation written in 100% Java
Jetty :: Websocket :: Client
Smack is an Open Source XMPP (Jabber) client library for instant messaging and presence. A pure Java library, it can be embedded into your applications to create anything from a full XMPP client to simple XMPP integrations such as sending notification messages.
Smack for standard XMPP connections over TCP.
Efficient, scalable, and flexible Java implementation of the Short Messaging Peer to Peer Protocol (SMPP)