been working for 2.5 months as a junior. First ever tech job.

I have nearly 6 YOE and still copy paste a unit test from a previous class instead of writing mine from scratch, because I'll probably forget some annotation or declaration, whatever.

it doesn't matter.

same thing for anything else. I don't know how to make a REST service from scratch right now. I could do it, with googling, but I'll just save my time and copy paste an existing service class from the project then editing and understanding what each line does while I go along, test it, debug it, see things that I unnecessarily copied, remove them, etc, etc clean the code, watch out for typical copy-paste fails

try your best, try to learn, chill. that guy sounds like an asshole.