I just spent the better part of 3 hours trying to get my Rails application logging with Log4j. I've finally got it working, but I'm not sure if what I did is correct. I tried various methods to no avail until my various last attempt. So I'm really looking for some validation here, perhaps some pointers and tips as well -- anything would be appreciated to be honest. I've summarized all my feeble methods into three attempts below. I'm hoping for some enlightenment on where I went wrong with each attempt -- even if it means I get ripped up. Thanks for the help in advance! System Specs Rails 3.0 Windows Server 2008 Log4j 1.2 Tomact 6.0.29 Java 6 Attempt 1 - Configured Tomcat to Use Log4J I basically followed the guide on the Apache Tomcat website here. The steps are: Create a log4j.properties file in $CATALINA_HOME/lib Download and copy the log4j-x.y.z.jar into $CATALINA_HOME/lib Replace $CATALINA_HOME/bin/tomcat-juli.jar with the tomcat-juli.jar from the Apache Tomcat Extras folder Copy tomcat-juli-adapters.jar from the Apache Tomcat Extras folder into $CATALINA_HOME/lib Delete $CATALINA_BASE/conf/logging.properties Start Tomcat (as a service) Expected Results According to the Guide I should have seen a tomcat.log file in my $CATALINA_BASE/logs folder. Actual Results No tomcat.log Saw three of the standard logs instead jakarta_service_20101231.log stderr_20101231.log stdout_20101231.log Question Shouldn't I have at least seen a tomcat.log file? Attempt 2 - Use default Tomcat logging (commons-logging) Reverted all the changes from the previous setup Modified $CATALINA_BASE/conf/logging.properties by doing the following: Adding a setting for my application in the handlers line: 5rails3.org.apache.juli.FileHandler Adding Handler specific properties 5rails3.org.apache.juli.FileHandler.level = FINE 5rails3.org.apache.juli.FileHandler.directory = ${catalina.base}/logs 5rails3.org.apache.juli.FileHandler.prefix = rails3. Adding Facility specific properties org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/rails3].level = INFO org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/rails3].handlers = 4host-manager.org.apache.juli.FileHandler Modified my web.xml by adding the following context parameter as per the Logging section of the jruby-rack readme (I also modified my warbler.rb accordingly, but I did opted to change the web.xml directly to test things faster). <context-param> <param-name>jruby.rack.logging</param-name> <param-value>commons_logging</param-value> </context-param> Restarted Tomcat Results A log file was created (rails3.log), however there was no log information in the file. Attempt 2A - Use Log4j with existing set up I decided to go Log4j another whirl with this new web.xml setting. Copied the log4j.jar into my WEB-INF/lib folder Created a log4j.properties file and put it into WEB-INF/classes log4j.rootLogger=INFO, R log4j.logger.javax.servlet=DEBUG log4j.appender.R=org.apache.log4j.RollingFileAppender log4j.appender.R.File=${catalina.base}/logs/rails3.log log4j.appender.R.MaxFileSize=5036KB log4j.appender.R.MaxBackupIndex=4 log4j.appender.R.layout=org.apache.log4j.PatternLayout log4j.appender.R.layout.ConversionPattern=%d{dd MMM yyyy HH:mm:ss} [%t] %-5p %c %x - %m%n Restarted Tomcat Results Same as Attempt 2 NOTE: I used log4j.logger.javax.servlet=DEBUG because I read in the jruby-rack README that all logging output is automatically redirected to the javax.servlet.ServletContext#log method. So I though this would capture it. I was obviously wrong. Question Why didn't this work? Isn't Log4J using the commons_logging API? Attempt 3 - Tried out slf4j (WORKED) A bit uncertain as to why Attempt 2A didn't work, I thought to myself, maybe I can't use commons_logging for the jruby.rack.logging parameter because it's probably not using commons_logging API... (but I was still not sure). I saw slf4j as an option. I have never heard of it and by stroke of luck, I decided to look up what it is. After reading briefly about what it does, I thought it was good of a shot as any and decided to try it out following the instructions here. Continuing from the setup of Attempt 2A: Copied slf4j-api-1.6.1.jar and slf4j-simple-1.6.1.jar into my WEB-INF/lib folder I also copied slf4j-log4j12-1.6.1.jar into my WEB-INF/lib folder Restarted Tomcat And VIOLA! I now have logging information going into my rails3.log file. So the big question is: WTF? Even though logging seems to be working now, I'm really not sure if I did this right. So like I said earlier, I'm really looking for some validation more or less. I'd also appreciate any pointers/tips/advice if you have any. Thanks!