What should I learn to develop a simple messenger?

Question

Java

The problem is this - I learn Java for like 2 months (I watched lessons and read books), but when I sit down to program on a PC, I understand that I don’t even know how to start and what to start. I decided that if I learn and apply knowledge at the same time, by writing a messenger, I will quickly get into programming, hence the question - what do I need to know to write a simple messenger of messages?

Answer 1

First you need to figure out how the machines communicate with each other (IP / Port).
Next, you need to configure the Socket, pull out the InputStream / OutputStream from the Socket. And already to work with streams.
In your case, I would learn JavaEE and understand JMS.