Yeah, now that I figured out how to use the “OAuth client credentials flow”, I just got myself an access token and the twitch4j method for getUser is working with that access token as first parameter.
I was a bit confused because I tried to go the website https://id.twitch.tv/oauth2/token
and it showed “404 page not found”, so for a second I thought that endpoint was outdated aswell, but you have to use postman or some http client to POST to it, then it returns normal error messages and once you give it valid parameters you actually get a token in your response.
I was trying all kinds of auth tokens with the twitch4j method for getUser and all returned a response saying invalid auth token which was very confusing.