...
Logging is one of the most important aspects of a production-grade server. A properly configured logging system is vital for identifying errors, security threats and usage patterns. All WSO2 products are shipped with the log4j logging capabilities, which generates all the administrative activities and server side logs.
Note that in addition to the logs from libraries that use Log4j, all logs from libraries (such as, Tomcat, Hazelcast and more) that use Java logging framework are also visible in the same log files. When Java logging is enabled in Carbon, only the Log4j appenders will write to the log files. If the Java Logging Handlers have logs, these logs will be delegated to the log events of the corresponding Log4j appenders. A Pub/Sub registry pattern implementation has been used in the latter mentioned scenario to plug the handlers and appenders. The following default log4j appenders are used for this implementation:
...