dkGirase/user-service — reverse-engineered prompt

Build me a small Java user service from this repo. I want it to run locally with the existing Maven setup and also work with the Dockerfile that’s already here.

The service should let another app manage users in a simple way. Add endpoints to create a user, get one user, list users, update a user, and delete a user. A user can have an id, name, email, and whatever basic timestamps make sense. Please include simple validation, like not allowing an empty name or a bad email, and return clear error messages instead of crashing.

If there’s already a database or framework in the project, use that. If not, keep it simple with in memory storage so I can run and test it right away. Add a basic health check, a few tests for the main behavior, and update any setup notes needed so someone can start it without guessing. Look up current docs online if you need to.