Gretty is a simple web framework for both building web servers and clients. Built on top of netty, it supports NIO style http server, asynchronous http client. It also supports both websocket server and client.
It's designed to be light weight and run as a standalone embedded solution.
It's written in Groovy++. But you can use it with pure Groovy, Scala or even Java.
Use Gretty Google Group for questions and general discussions about Gretty.