Logging in Apache Tomcat is implemented with the help of
Apache Commons Logging
library. That library is a thin wrapper above different logging
frameworks. It provides Tomcat with the ability to log
hierarchically across various log levels without the need to rely on a
particular logging implementation.
Since Tomcat 6.0, Tomcat uses a private package-renamed implementation of
Apache Commons Logging, to allow web applications to use their own
independent copies of the original Apache Commons Logging library.
In the default distribution this private copy of the library
HTTP/1.1 403 Forbidden