Simple multithreaded java server done during my 1st year of Master.
Go to the source directory
cd java-chat-server
Compile
javac -classpath src/ src/Main.java
Run giving as argument a port to listen (eg. 12345) and a max client capacity (at least 2, chatting with yourself doesn't make sens)
java -classpath src/ Main <port> <capacity>
Start as much client that you want. Beyond capacity, others client will be on the waiting list.
netcat localhost <port>