Configure log4j in weblogic server

I have recently configured log4j for our web applications deployed in weblogic 10.3 domain. The steps are given below:

1. Copy log4j-1.2.9.jar & wllog4j.jar under domain_root/lib folder.
2. Create log4j.xml and drop it under domain_root folder. If you have log4j.xml inside the application(EAR/WAR), I would recommend to move outside EAR/WAR as changing severity (log level) would require re-deployment. To avoid this, we can move log4j.xml into domain root folder but again the server needs to be bounced. But there is a fix. Click here for more info.
3. Login to weblogic server console. Go to Servers ->  Admin Server-> Logging. Click on advanced mode. Change the logging implementation from JDK to Log4J. Click save.
4. Activate changes. Re-start the admin server.

This should enable log4j and should write logging into log file mentioned in log4j.xml or properties file.

Hang on! There is a catch here. Say now I want to change the log level from DEBUG into WARN or ERROR. How do i do? We go to log4j.xml and change the level. Now how does this change take into effect? It needs bouncing of the server. That part i didn't like it. But guess what I have a solution for this. Please click here for changing the log levels on the fly at run time. Log4jAdmin.jsp will do the trick.

Some of our readers asked for example of log4j.xml. If you google it you will get plenty of them, still I am honoring your requests. Here you go, folks:

log4j.xml:
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration> 
  <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern"
             value="%d [%t] %-5p %c - %m%n"/>
    </layout>
  </appender> 
<appender name="FILE" class="org.apache.log4j.RollingFileAppender">
    <param name="File" value="/log/myApp.log"/> 
    <param name="Append" value="true"/>
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%d{ISO8601} %t %-5p %c{2} - %m%n"/>
    </layout>
  </appender>
  <logger name="org.apache">
    <level value="WARN"/>
  </logger>
  <logger name="org.springframework">
    <level value="WARN"/>
  </logger>
  <root>
    <level value="DEBUG"/>
    <appender-ref ref="FILE"/>
<!--   <appender-ref ref="CONSOLE"/> -->
  </root>
</log4j:configuration>

I have disabled log4j to write into weblogic console by commenting out. If you want to enable it just uncomment it and bounce the server, you are done!