When a Spring Boot app starts up with default (INFO) logging, there are some noticeable gaps (pauses). It's worth focusing on the gaps when looking for efficiency savings because of the amount of time they take, and because no-one bothered to log anything, so the chances are the app is doing something repetitive. We can tweak the logging levels to try and fill in the gaps and find out what is going on in there.
Basic empty web app with actuators has three such gaps:
0 1410ms
|------|---------------------------|-----|------|---------|--------|--------|
| 578 | |144(5)| | 133(6) |