It works, it's simple, you can read the entire source in about 10 minutes. It doesn't HAVE to be improved or changed - the purpose was to provide copy/pasteable code that anyone could steal and use as the starting point to create their own server designs and implementations.
But I do get people often telling me its been really useful and that they want to extend it.
I'm currently not doing any java server work, and probably won't be for the next 12 months, so I'm not the best person to maintain this any more. I think there's some good things that could be done with it. Personally, if I were playing with it right now, I'd like to take the best bits of this and Riven's nice work on simplifiying NIO with TCP/UDP (here: http://www.java-gaming.org/topics/nio-wrapper-tcp-udp/18720/view.html
) and make something a bit more usable than the "strings-only server" that I created here. NB: solely to show a "simplest possible" way of getting UDP working with NIO.
NB: this is in NO WAY a replacement for things like MINA, JGN, etc. This is really just for people who want "The simplest possible NIO server implementation that I personally can understand myself and experiment with", and who then might decide to stop playing and start using a bigger, better library like the others - or decide to write their own.
JGO thread about the server here - http://www.java-gaming.org/topics/simple-nio-nonblocking-server-with-source-code/18077/view.html