Project doc [1] mention following options:

• Default JULI - for all logging (Tomcat internals and applications)
• log4j - Applications only
• log4j - Tomcat internals and applications

Default JULI - for all logging (Tomcat internals and applications)

• This is default behavior, no additional effort is needed - for details see [2]

Log4j - Applications only

• cp JWS_HOME/extras/log4j-eap6.jar WEBAPP_PATH/WEB-INF/lib
• cp JWS_HOME/extras/log4j.properties WEBAPP_PATH/WEB-INF/classes
• more details [3]

Log4j - Tomcat internals and applications

• cp JWS_HOME/extras/log4j-eap6.jar CATALINA_HOME/lib
• cp JWS_HOME/extras/log4j.properties CATALINA_HOME/lib
• cp JWS_HOME/tomcatX/tomcat-juli.jar CATALINA_HOME/bin
• cp JWS_HOME/tomcatX/tomcat-juli-adapters.jar CATALINA_HOME/lib
• Tomcat's internal logging will be present in CATALINA_HOME/logs/tomcat.log
• Web applications should certainly use their own log4j configuration
• more details [3]
• WARN: There is issue https://issues.jboss.org/browse/JWS-653 affecting described setup

[1] https://tomcat.apache.org/tomcat-8.0-doc/logging.html
[2] https://tomcat.apache.org/tomcat-8.0-doc/logging.html#Using_java.util.logging_(default)
[3] https://tomcat.apache.org/tomcat-8.0-doc/logging.html#Using_Log4j