Can socketio-java currently be integrated with play framework? Since it's servlet based, and play is not, I don't see how this would work.

Also, i would be nice to have socketio-java to work with netty, since play works with netty it could make a nice companion to play.

No, socketio-java does not work with play. It has only been tested in jetty and may work with other Servlet 3.0 containers (e.g. Tomcat 7).