For a personal game jam I created this Java networking package. It handles all of the server/client connection code, the sending of object, and the reading of objects. I based it off the Kyronet public library, but used Multithreading and Sockets instead of singlethreaded Socket Channels.
Very simple to use and set up (as seen in test folder), and works well enough for my personal projects that need a active client/server network system.