Tapestry makes use of the Apache group's Log4J package to perform logging. This is an easy, fast, powerful framework for adding logging to any Java application. Using Log4J, any number of categories can be created, and a logging priority for each category assigned. Tapestry uses the complete class name as the category for each class.
The ApplicationServlet class includes a method, setupLogging(), to initialize Log4J. The provided implementation is sufficient for testing (see the Javadoc for more information) but serious applications may want to create a more involved logging configuration.
The Tapestry Inspector includes a Logging tab that allows the logging configuration to be dynamically changed. The logging priority for any category can be assigned, and new categories can be created.
What this means is that, using the Inspector, it is possible to control exactly what logging output is produced, dynamically, while the application is still running. The Tapestry Inspector is easily added to any Tapestry application. More information on the Inspector is provided in a later section.