madhusamala-dev/spring-security-jwt — reverse-engineered prompt

Build me a simple Java backend that demonstrates login with JWT using Spring Security. I want someone to be able to create an account, log in with their username and password, get a token back, and then use that token to access a protected test endpoint.

Keep it small and easy to understand, since this is mainly for learning and as a starter project. Add a public health or welcome endpoint, a protected user endpoint, and clear responses when the token is missing, expired, or invalid. Use a clean project structure and include enough comments so I can follow what each part does.

Please make sure it runs with Maven from the command line, and add a short README explaining how to start it and test the login flow with sample requests. Look up the current Spring Security docs online if you need to.