On the following page http://logging.apache.org/log4j/2.x/manual/webapp.html, at the section entitled "Servelet 2.5 Web Applications", there are references to the following listener and filter classes -
When the web.xml settings provided in this particular section are used in conjunction with Apache Tomcat, Tomcat logs a relatively obscure error to the effect the relevant listener and filter could not be started.
The problem has been traced to an incorrect classpath. The correct classes and associated classpaths ought to be -
"core" has been omitted from each. For the benefit of future log4j2 developers, it may be helpful to update the documentation to refer to the correct classes.