A Logger is the entry point to logs messages.
The main entity on which applications make logging calls. A Logger object is used to log messages.
Loggers may be assigned levels. For instance, TRACE, DEBUG, INFO, WARN and ERROR
The level filter the messages by their severity that this logger will append.
Example: A logger level of warning will not log any info message.
The effective level for a given logger is equal to the first non-null level in its hierarchy, starting at itself and proceeding upwards in the hierarchy towards the root logger.
Example:
The root logger has by default a level (generally DEBUG)
A static logger factory is the entry point to get or create a logger
Example:
// get the fully qualified name of the class by default
protected static final Logger logger = LogManager.getLogger();
Logger x = LoggerFactory.getLogger("x.y.x");