Logging is one of the most important aspects of a production grade server. A properly configured logging system is vital in identifying errors, security threats and usage patterns. WSO2 ESB uses a log4j based logging mechanism through Apache Commons Logging facade library. The log4j.properties file which governs how logging is performed by the server can be found in ESB_HOME/lib directory.
Note
It is not recommended to make any alterations to the default log4j.properties file.
The proper way of setting up logging is by using the ESB management console. Any changes to the logging configuration you make from the management console will get priority over what is defined in the actual log4j.properties file.
A Logger is an object used to log messages for a specific system or application component. Loggers are normally named, using a hierarchical dot-separated namespace and have a “child-parent” relations. For example, the logger named "root.sv" is a parent of the logger named "root.sv.sf" and a child of “root.”