SL4JF in Tomcat not showing up in log files

Question

I have installed Tomcat, and using SLF4J as our logging framework. I copied slf4j-api-1.6.4.jar and slf4j-jdk14-1.6.4.jar into the Tomcat library i.e $TOMCAT_HOME/lib.

I assumed that if I use SLF4J, it shall delegate to java.util.Logger, which will delegate to underlying Tomcat logging framework. But when I deploy and check my application, I don't see anything getting logged. All my exception/log information is getting lost.

Is my understanding right, or did I miss anything to keep in class-path?

Vickeyvicki

Your configuration seems correct to me, please add your JUL configuration file (logging.properties). – Interpreter

You can see github.com/grgrzybek/tomcat-slf4j-logback for a project that replaces Tomcat JULI with pure SLF4J+Logback which doesn't conflict with individual WARs logging configuration – Hewie

foch, I use the default logging.properties which gets shipped with the server installation. Grzegorz Grzybek, thanks for the link. but i want to know why by defalt its not working. this means SL4J is not useful if we are using tomcat? – Vickeyvicki

@Surya: Tomcat (since version 6.0) uses a private package-renamed implementation of Apache Commons Logging (see this page). It just doesn't know how to use SLF4J. – Hewie

Answer 1

Instead of copying the slf4j-api-1.6.4.jar and slf4j-jdk14-1.6.4.jar under $TOMCAT/lib, i shipped these jars with the war application. in this case my exceptions are getting logged.

Vickeyvicki

Which configuration file the was picked up when you ship these jars with the war application? This is totally different from what you asked initially. – Sling

@Surya, many many thanks for the question and answer. Recently, I just started using TomEE 1.5.1 (tomcat 7.0.32+), and I was trying to get my exceptions and logs out to catalina log file while running TomEE as Windows service (via tomcat7 windows service), and I searched and searched this topic for hours, and this answer finally helped me. thank you so much! – Irrefragable

Answer 2

Probably what you need is to add the system property to the your CATALINA_OPTS.

For Windows systems, add to your %CATALINA_HOME\bin\catalina.bat file:

set CATALINA_OPTS=-Djava.util.logging.config.file=\PATH\TO\YOUR\logging.properties

or on Linux/UNIX systems, add to your $CATALINA_HOME/bin/catalina.sh file:

CATALINA_OPTS=-Djava.util.logging.config.file=/PATH/TO/YOUR/logging.properties

Don't forget that in Linux/UNIX systems, you need to quote if you have more than one parameters in the CATALINA_OPTS, e.g.

CATALINA_OPTS="-Xmx256m -Djava.util.logging.config.file=/PATH/TO/YOUR/logging.properties"

This line is to ensure that your logging.properties file is being loaded when Tomcat is started.

Sling

I can see log file filled when an exception is thrown from my application. but when i try to log explicitly its failing. also when i checked the catalina.sh, i can see that logging.properties is being set to the correct properties file – Vickeyvicki

Answer 3

You can configure Tomcat to use log4j as described in its docs, put log4j.properties to $CATALINA_HOME/lib directory and use slf4j-api with slf4j-log4j12 bridge. So you've got clean slf4j API and log4j goodness like DailyRollingFileAppender etc.

Mariammarian

the question is about "java.util.Logger" - the default logging for tomcat and not about log4j. – Rubenrubens