Generate open API json/yaml from Java endpoints (jax-rs)

I've been working on a service that has something like 80 ~ 90 endpoints in differents controllers developed in JAX-RS (A really anciest project, that didn't even uses Maven).

Is there any way to generate automagically an open api documentation by using the javadoc and annotations of the endpoints?

I have intellij ultimate, so looking at the endpoint tab, if I could just copy all of those methods in a scratch file or something to do multiediting would be great.

But if the IDE can do it for me, it would be even nicer. I know that intellij can generate code from openAPI specification, i need to do just the opposite.

Thanks