My production systems don't generally log; they're busy serving (I once worked on a hard real-time embedded air traffic control system where production logging was literally a single bit of information - a logic level that went high when the processor was busy, and low on idle - so we could measure our timing safety margin with an oscilloscope)
Test systems log at debug except for low level packages that insist on ridiculous logging (Hibernate, http client - and both of those have ANOTHER level of hacks to do wire-level logging in addition to the standard stuff).
Logging is just so painful, and not just in Java. Debian switched to rsyslog some time ago and I am still seeing no benefit at all, yet have to learn yet another half-arsed buggy scripting language to achieve simple things like, oh, not having my DHCPD logs showing up in three different files. FFS people.