Low-level telnet library in Java using Non-Blocking NIO.
This is neither a Telnet server nor a Telnet client, but it provides enough of a framework to build them. The only thing you have to do is give it a SocketChannel.
This library uses NIO. In particular, it uses net.virtualinfinity.nio which is a thin Event Queue wrapper around NIO select().
This code is ready to use, but it isn't complete. There are a lot of Telnet options which would be useful to implement.
The code is also likely to evolve quite a bit before the archetecture stablizes. In particular, the "remote" vs "local" option handling needs to be better separated.
The set of built-in option handlers also needs to be expanded, but it is easy enough to supply your own.