The class loading magic means you need to be exceptionally careful about things that would otherwise be very innocuous. It’s the rule, not the exception - that your average spring boot app will be doing tons of expensive stuff at startup. Most of which is unnecessary and was not even intended.

The JVM doesn’t need this kind of thing either, and it gets a bad wrap from the J(2)EE days, and the “simple” replacement that Spring was supposed to be.

No doubt there’s some benefits to be had, but I don’t think the trade-offs are worth it, especially at larger scales.