KryoNet is a free and open source Java library that provides a clean and simple API for efficient TCP and UDP client/server network communication using NIO.
KryoNet uses the Kryo serialization library to automatically and efficiently transfer object graphs across the network.
KryoNet runs on both the desktop and on Android.
KryoNet is ideal for any client/server application. It is very efficient, so is especially good for games. KryoNet can also be useful for inter-process communication.
Detailed instructions on how to install and use the KryoNet utility on your Mac are available HERE.