What is the purpose of the log4j configuration file?

The purpose of the log4j configuration file is to define the output location, format, and level of logs. It is used to configure the behavior of log4j loggers, including determining the log targets, specifying log format, defining log levels, and more. The configuration file can define multiple loggers, each with different configurations, in order to record different levels of log information as needed. Through the configuration file, logs can be output to different targets such as console, file, database, etc., and log formats can be defined, such as date-time, log level, class name, thread number, etc. The configuration file can also set log levels to determine which levels of logs should be recorded. By modifying the configuration file, the log behavior can be easily changed without the need to modify the code.