Commons Logging

Put the commons-logging.jar to classpath of the tomcat, NOT to /WEB-INF/lib

In /WEB-INF/classes folder, create commons-logging.properties file containing:
org.apache.commons.logging.Log=org.apache.commons.logging.impl.SimpleLog

In /WEB-INF/classes folder, create simplelog.properties file containing:
org.apache.commons.logging.simplelog.defaultlog=debug