Vert.x is the framework for the next generation of asynchronous,
effortlessly scalable, concurrent web applications.

It is an event driven application framework that runs on the JVM
- a run-time with real concurrency and unrivalled performance.
Vert.x then exposes the API in Clojure, DynJS, Groovy, Java,
JavaScript, Ruby, PHP, Python, and Scala.
So you choose what language you want to use.

WWW: http://vertx.io/