When it comes to Web development, Ruby has the Sinatra framework and Node.js has Express.js. Now, Java has micro Web framework Jooby.
Built by developer Edgar Espina, Jooby offers modular, stateless application development leveraging NIO (non-blocking IO) servers including Netty, Jetty, or Undertow.
More about Java microframeworks
See Jump into Java microframeworks to get started with Spark, Ninja, and Play: Three more Java web frameworks optimized for ultra-lightweight development.