Java Application Logging Guidelines

Here are some guidelines or "best practices" for logging; they're hard-earned lessons from my own 17+ years' experience writing Java code as well as several other sources.

First and foremost: use slf4j​ exclusively as logging API, with logback ​as the underlying logging implementation.​ slf4j is a flexible API that can utilize any of the popular logging frameworks (logback, log4j, java.util.logging, etc) at runtime to provide the low-level logging implementation. As such, the only dependency in application components should be on the slf4j API; no class should reference any other logging interfaces.

Read your logs often to spot incorrectly formatted messages.​ 

This seems obvious, but I'm always surprised/appalled by how many developers blindly send stuff to log without ever looking at most of it in runtime. If you read nothing else in these guidelines, please please please at least heed this advice.