This is just the complexity in individual files! Configuration can be a lot more complicated. Look at dockerfiles, which are filesystems overlaid over each oth

This is just the complexity in individual files! Configuration can be a lot more complicated. Look at dockerfiles, which are filesystems overlaid over each other, often sourced from the internet. https://docs.spring.io/spring-boot/reference/features/external-config.html https://docs.spring.io/spring-boot/reference/features/extern... Look at that: a massive 15 deep precedence order for pulling just individual values (oh man, doesn't even touch things like maps/lists that get merged/overridden). That includes sources like the OS, environment-specific, a database (the JNDI registry), XML, JSON, .properties files, hardcodes. Honestly, I remember this being even deeper, I suspect they have simplified this. This doesn't even get into secrets/secured configuration, which may require a web service invocation. I used to also pull config via ssh, or from private gits or github, from aws web service calls (THAT required another layer of config getting a TOTP cycled cred). https://crushedby1sand0s.blogspot.com/2021/02/stages-of-despair-in-configuration.html https://crushedby1sand0s.blogspot.com/2021/02/stages-of-desp... I was right, the Spring config fallthru was deeper.