This is how log4j works
This is how it works. The main objects/configs in the log4j framework that we work with are loggers, appenders, layouts, patterns,and log-levels.
| Object/Concept | Description |
|---|---|
| Logger | Loggers are objects with given names through which application makes logging calls. Every logger has one or more appender tied to it. |
| Appender | An appender is the destination where logs are recorded, for eg. console, file, db etc. |
| Layout | Alayout is tied to an appender and determines the format of logged messages for eg., plain text, xml format, html format etc. |
| Pattern | A pattern is tied to a layout and determines the fields that are logged in message besides the given message string, for eg. timestamp, class name, method name, line number etc. |
| Log Level | The only other thing that you need to know about log4j to get going is the concept of log-level. See, when you write logs in your app, you can specify the criticality or level of log, say for example ordinary log, important log or critical log . Now you can configure log4j to print logs whichare ordinary or a higher level. So, you can choose at run-time, the verbosity of logs. |