Page History

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• Prior to Tomcat 5.5, Tomcat provided a Logger element that you could configure and extend according to your needs.
• Starting with Tomcat 5.5, Logger was removed and Apache Commons-Logging Log is used everywhere in Tomcat. Read the Commons-Logging documentation if you'd like to know how to better use and configure Tomcat's internal logging. See also http://tomcat.apache.org/tomcat-8.0-doc/logging.html
• In Tomcat 7 (and also 6), the logging code is based on a set of classes interacting with the java.util.logging API (JUL), which comes with Java since version 1.4. The Tomcat startup script configures the JVM to use a web-application-aware implementation of the JUL LogManager. This Tomcat logging infrastructure is called JULI, and one can still distinguish its Apache Commons Logging heritage, but the complex configuration has been edited out and the package name changed.
  

http://public.m-plify.net/TomcatLogging.png

Web applications can get logging service by using the Servlet API logging (which not recommended), the JUL interface (which ultimately goes to JULI) or any other preferred interface for which they furnish the jar files and the appropriate configuration (see the respective descriptions for Log4J, SLF4J, logback or Apache Commons Logging for example).

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