Example Spring Boot Hello World application.
This uses Gradle to build a Spring Boot Web Application which responds to GET / with "hello"
It exposes a management interface on port 8081 because that might be a useful thing when running on internal networks. Tools like Prometheus running internally can query metrics from that port, and similarly load-balancers/orchestration things can do health check/liveness probes against that port. But it does not need to be exposed to external traffic.