Jodd uses SLF4J for internal logging. The Simple Logging Facade for Java or (SLF4J) serves as a simple facade or abstraction for various logging frameworks, e.g. java.util.logging, log4j and logback, allowing the end user to plug in the desired logging framework at deployment time.
By default, Jodd comes with the simple implementation of SLF4J facade that logs messages of level INFO or higher on the console (System.err). Please refer to SLF4J documentation for more info on binding it into your existing logging framework. If you still haven't choose a logging framework, consider logback.
Only Jodd Wot (bundle of several frameworks) uses logging. We are not logging aggressively, instead, we tried to put logging only on important points and things that happens far in background. In that manner, for example, exceptions are not logged - it is expected that some above layer that is using Jodd frameworks handles (and logs) exceptions.