Netty 2's interesting features are:
- Each messages of the user defined protocol are mapped to message classes; Protocols are maintainable in object-oriented way such as inheritance and polymorphism.
- Utilizes Java NIO.
- Thread pooling is implemented out-of-the-box.
- NIO direct buffer is reused to reduce direct buffer allocation overhead.
- I/O threads and event process threads are separated to avoid I/O to slow down from business logic.
Check out Netty 2 at: http://gleamynode.net/dev/projects/netty2/