Example for a chat program in java.
You need at least one instance of Server and two of Client in order to try
it out.
With IntelliJ open the project. Select the Server class and hit Shift+Alt+F10, or select
Run ==> Run... from the menu. Do the same with the Client-class. Once you have created
run configarations (by using Alt or selecting Run...) you can
start the client or server directly by selecting those configurations from the run menu or hitting
Shift+F10 or choosing Run ==> Run (Server|Client).
If you test this on a local machine fill in 127.0.0.1 as the IP-adress in all open clients and
choose an arbitrary name.