Reinstating this question with a bounty! I need an example that stays online, like a real instant messenger! It needs to always be ready to receive or send a message to an arbitrary address over an arbitrary port, using TCP. The program must not quit after sending/receiving a message.
Bounty goes to whoever can give the best example of a real, usable instant messenger.
Looking online, all resources I found are either useless tutorials, dead threads, dead tutorials, ancient examples, or tell the programmer to use external APIs. How can I create a basic instant messenger from the ground up, only using Java SE?
There must be a way to do this, and some sample code would be appreciated. It only needs to perform the simplest tasks: Check if a compatible client is online on another computer (IP will be provided by the user) and send a TCP packet to that client, which will receive and display its contents.
First few Google results for “java socket chat“:
Or from “java 8 chat client“:
Many, many results following in the search. Pick one that suits your needs. You can even modify the Google search to only show results from the past year, if you wish.