As we said, by default Oracle Weblogic server use the JDK Logging implementation. You can anyway switch to Log4j (http://logging.apache.org/log4j) configuration if you feel more comfortable with it. That will anyway require a few steps to complete it:
1. At first, from the Advanced Logging screen, select Log4j as the Logging implementation as shown by the following picture:
2. Now enter your Server’s configuration screen and select Configuration | Server Start. From there, add as properties the log4j configuration file name and set the property weblogic.log.Log4jLoggingEnabled to true as shown by the following snapshot:
Remember that the log4j.properties (or log4j.xml) file needs to be included into Weblogic classpath; thus, supposing that you have placed it into the folder “C:\Weblogic\user_projects\domains\base_domain\config”, then you need adding this directory into the server Classpath text item.
The following log4j.properties defines a RollingFileAppender which will write logs to your domain root directory:(C:\Weblogic\user_projects\domains\base_domain)
log4j.appender.rollingFile=org.apache.log4j.RollingFileAppender log4j.appender.rollingFile.File=mylog.log log4j.appender.rollingFile.MaxFileSize=2MB log4j.appender.rollingFile.MaxBackupIndex=2 log4j.appender.rollingFile.layout = org.apache.log4j.PatternLayout log4j.appender.rollingFile.layout.ConversionPattern=%p %t %c - %m%n log4j.rootLogger = INFO, rollingFile
Last effort, since WebLogic Server does not load any Log4j library in your domain, will be to include log4j in the DOMAIN_HOME/lib subdirectory. Place there a Log4j implementation (log4j-X.X.X) and Weblogic’s Log4j libraries (wllog4j.jar) which are part of the server distribution.