Im generating a REST database service for an android application to connect to, and have little to no security experience. the service currently uses OAuth2 to secure a web front end with a Spring Boot application. I want to expose a REST service for an android application to access the same data.
My question is this, users are authenticated via the android app, but how can I also secure the REST endpoint for that user to access the endpoint in the same session?
Im not looking so much for an implementation as I am a direction/ technologies that are used so I can learn.