There used to be really prominent banners telling you about it. I don't see them now, but I'm also not sure they switched back. Here's an article I found explaining the switch to requiring paid usage.
The 2021 license change reverted this somewhat, by giving you one year of security fixes for free in the long term support versions (I’m sure I’m missing some detail, if not completely misinterpreting things, here)
https://blog.netwrix.com/2021/12/02/oracle-java-license-chan...