Alternate Cometd implementation: Awaken the Grizzly!
Grizzly Asynchronous Request Processing (ARP) is becoming more and more used. Brian McCallister already blogged about a very good example, Andreas Egloff implemented its SOA HTTP BC on top of it, and Jonas Jacobi and John Fallows were the first to implement the Bayeux protocol on top of ARP. They recently wrote an article about it called Enterprise Comet: Awaken the Grizzly!. If you are interested about Cometd, I recommend you read it. Technically, their examples can be run using Jetty Comet/Cometd implementation and gCometd!. Wow!