I've made a simple wrapper for socket.io (
https://github.com/socketio/socket.io-client-java) that I use for my own project, if anyone's interested. It's not complete, though - it supports connect, emit, send, disconnect & on events (with one parameter only as JSON string) - no ack & other fancy stuff, sorry. For that reason, and the lack of documentation, I will not publish it as a library, but I will gladly send it to anyone interested with short instructions - it is very easy to use. While on the topic of node.js stuff, earlier I made a complete wrapper for Meteor DDP protocol (
https://github.com/delight-im/Android-DDP). If someone needs one of these let me know.