Weighing around 50KB, rupy is probably the smallest Java NIO application server in the world.

Rupy is inherently non-blocking asynchronous, which makes it the ideal candidate for high concurrency real-time applications pushing dynamic data.

Tested with acme, rupy performs on average ~1500 requests per second. To put that figure in perspective; acme doesn't use keep-alive, so that means 1500 new TCP connections serving dynamic content per second!

If you want a real-world example of rupy in action head over to sprout; a simple blogger.

Jetty has always been a light(er) weight faster Java webserver with more up to date standards. As of Jetty 7 is now osgi enabled and comes with a commet server.

It is also a pain in the ass to run from the standard eclipse and still only works typically with the Eclipse Plugin Run Jetty Run

Note: remove the HTTPS port from the plugin if you don't want the hassle of creating a key-store.