Using Log4j

This section explains how to configure Tomcat to use log4j rather than java.util.logging for all Tomcat’s internal logging.

The steps described in this section are needed when you want to reconfigure Tomcat to use Apache log4j for its own logging. These steps are not needed if you just want to use log4j in your own web application. — In that case, just put log4j.jar and log4j.properties into WEB-INF/lib and WEB-INF/classes of your web application.

The following steps describe configuring log4j to output Tomcat’s internal logging.

• Create a file called log4j.properties with the following content and save it into $CATALINA_BASE/lib

log4j.rootLogger = INFO, CATALINA

# Define all the appenders

log4j.appender.CATALINA = org.apache.log4j.DailyRollingFileAppender

log4j.appender.CATALINA.File = ${catalina.base}/logs/catalina

log4j.appender.CATALINA.Append = true

log4j.appender.CATALINA.Encoding = UTF-8

# Roll-over the log once per day

log4j.appender.CATALINA.DatePattern = ‘.’yyyy-MM-dd’.log’

log4j.appender.CATALINA.layout = org.apache.log4j.PatternLayout

log4j.appender.CATALINA.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

 

log4j.appender.LOCALHOST = org.apache.log4j.DailyRollingFileAppender

log4j.appender.LOCALHOST.File = ${catalina.base}/logs/localhost

log4j.appender.LOCALHOST.Append = true

log4j.appender.LOCALHOST.Encoding = UTF-8

log4j.appender.LOCALHOST.DatePattern = ‘.’yyyy-MM-dd’.log’

log4j.appender.LOCALHOST.layout = org.apache.log4j.PatternLayout

log4j.appender.LOCALHOST.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

 

log4j.appender.MANAGER = org.apache.log4j.DailyRollingFileAppender

log4j.appender.MANAGER.File = ${catalina.base}/logs/manager

log4j.appender.MANAGER.Append = true

log4j.appender.MANAGER.Encoding = UTF-8

log4j.appender.MANAGER.DatePattern = ‘.’yyyy-MM-dd’.log’

log4j.appender.MANAGER.layout = org.apache.log4j.PatternLayout

log4j.appender.MANAGER.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

 

log4j.appender.HOST-MANAGER = org.apache.log4j.DailyRollingFileAppender

log4j.appender.HOST-MANAGER.File = ${catalina.base}/logs/host-manager

log4j.appender.HOST-MANAGER.Append = true

log4j.appender.HOST-MANAGER.Encoding = UTF-8

log4j.appender.HOST-MANAGER.DatePattern = ‘.’yyyy-MM-dd’.log’

log4j.appender.HOST-MANAGER.layout = org.apache.log4j.PatternLayout

log4j.appender.HOST-MANAGER.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

 

log4j.appender.CONSOLE = org.apache.log4j.ConsoleAppender

log4j.appender.CONSOLE.Encoding = UTF-8

log4j.appender.CONSOLE.layout = org.apache.log4j.PatternLayout

log4j.appender.CONSOLE.layout.ConversionPattern = %d [%t] %-5p %c- %m%n

 

# Configure which loggers log to which appenders

log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost] = INFO, LOCALHOST

log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager] =\

 

INFO, MANAGER

log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager] =\

INFO, HOST-MANAGER

• Download Log4J (v1.2 or later).
• Download or build tomcat-juli.jar and tomcat-juli-adapters.jar that are available as an “extras” component for Tomcat.

This tomcat-juli.jar differs from the default one. It contains the full Apache Commons Logging implementation and thus is able to discover the presense of log4j and configure itself.

• If you want to configure Tomcat to use log4j globally:
• Put log4j.jar and tomcat-juli-adapters.jar from “extras” into $CATALINA_HOME/lib.
• Replace $CATALINA_HOME/bin/tomcat-juli.jar with tomcat-juli.jar from “extras”.
• If you are running Tomcat with separate $CATALINA_HOME and $CATALINA_BASE and want to configure to use log4j in a single $CATALINA_BASE only:
• Create $CATALINA_BASE/bin and $CATALINA_BASE/lib directories if they do not exist.
• Put log4j.jar and tomcat-juli-adapters.jar from “extras” into $CATALINA_BASE/lib
• Put tomcat-juli.jar from “extras” as $CATALINA_BASE/bin/tomcat-juli.jar
• If you are running with a security manager, you would need to edit the$CATALINA_BASE/conf/catalina.policy file to adjust it to using a different copy of tomcat-juli.jar.
• Note: This works because libraries, if they exist in $CATALINA_BASE, are loaded in preference to the same library in $CATALINA_HOME.
• Note: tomcat-juli.jar is loaded from $CATALINA_BASE/bin not $CATALINA_BASE/lib as it is loaded as part of the bootstrap process and all the bootstrap classes are loaded from bin.
• Delete $CATALINA_BASE/conf/logging.properties to prevent java.util.logging generating zero length log files.
• Start Tomcat

This log4j configuration mirrors the default java.util.logging setup that ships with Tomcat: both the manager and host-manager apps get an individual log file, and everything else goes to the “catalina.log” log file. Each file is rolled-over once per day.

You can (and should) be more picky about which packages to include in the logging. Tomcat defines loggers by Engine and Host names. For example, for a more detailed Catalina localhost log, add this to the end of the log4j.properties above. Note that there are known issues with using this naming convention (with square brackets) in log4j XML based configuration files, so we recommend you use a properties file as described until a future version of log4j allows this convention.

 

log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost]=DEBUG

log4j.logger.org.apache.catalina.core=DEBUG

log4j.logger.org.apache.catalina.session=DEBUG

 

Be warned: a level of DEBUG will produce megabytes of logging and slow startup of Tomcat. This level should be used sparingly when debugging of internal Tomcat operations is required.

Your web applications should certainly use their own log4j configuration. This is valid with the above configuration. You would place a similar log4j.properties file in your web application’s WEB-INF/classes directory, and log4jx.y.z.jar into WEB-INF/lib. Then specify your package level logging. This is a basic setup of log4j which does *not* require Commons-Logging, and you should consult the log4j documentation for more options. This page is intended only as a bootstrapping guide.

Additional notes

• This exposes log4j libraries to the web applications through the Common classloader.
• Because of that, the web applications and libraries using Apache Commons Logging library are likely to automatically choose log4j as the underlying logging implementation.
• The java.util.logging API is still available for those web applications that use it directly. The${catalina.base}/conf/logging.properties file is still referenced by Tomcat startup scripts.
• Removal of ${catalina.base}/conf/logging.properties file, mentioned as one of the steps above, causes java.util.logging to fallback to the default configuration for the JRE, which is to use a ConsoleHandler and therefore not create any standard log files. You should confirm that all your log files are being created by log4j before disabling the standard mechanism.
• The Access Log Valve and ExtendedAccessLogValve use their own self-contained logging implementation, so they cannot be configured to use log4j. Refer to Valves for specific configuration details.