This post is a simple reminder to myself on how to change the logging of Liferay 5.1.2. I have a simple install of Liferay on tomcat 6.0. To change logging, just edit webapps\ROOT\WEB-INF\classes\log4j.properties and restart the server. I added this line: log4j.category.com.liferay.portal=DEBUG to get lots of debug information in my logs.