WDYT please, @christophstrobl and @sdeleuze?

Will the warning be also printed when doing a regular shutdown of the application?

Yes, I believe so. If org.crac.Resource is on the classpath then HikariCheckpointRestoreLifecycle will be auto-configured. The log message will then be output irrespective of the type of shutdown that's being performed.

Adding the shutdown time is a nice addition, though I think it should be formatted with a reasonable time unit.
Not so sure about the warning log message for suspension. Thought the requirement for pool suspension had been documented/is easy to find.

I don't see it in https://docs.spring.io/spring-boot/reference/packaging/checkpoint-restore.html, where could I have read about it?
I think as long as crac is on classpath, users will consider using checkpoints at some point and the warning message would point them in the right direction.

the link in the docs seem to be broken.

... resources such as socket, files and thread pools on a limited scope.

...so the info is not as easy to be found as I had assumed.

#42938 should have fixed the link to the status page.

Thanks @deki !