Logging done right gives you everything you need to diagnose production issues. Done wrong, it either buries you in noise or leaves you blind. This article covers the full logging stack — from basics to structured production logging. The Logging Stack Your Code → SLF4J API → Logback (implementation) → Appenders (console, file, etc.) SLF4J is the facade — your code always calls LoggerFactory.getLogger() and log.info(). The implementation (Logback) is swappable without changing your code.