Java-sockets-threads-example is a project mainly written in Java, based on the MIT license.
An example application showing how to build a muilti-threaded chat client and server in Java
This project contains the sample code I use while teaching Sockets and Threads (concurrent programming) in my Java classes. The main idea is that when programming concurrent code in java you should use as little explicit synchronization as possible and everyting should be done by message passing.