### Logger hierarchy
- Named Hierarchy
A logger is said to be an ancestor of another logger if its name followed by a dot is a prefix of the descendant logger name. A logger is said to be a parent of a child logger if there are no ancestors between itself and the descendant logger.
- root logger
- it always exists,
- it cannot be retrieved by name.
- Level Inheritance
The inherited level for a given logger C, is equal to the first non-null level in the logger hierarchy, starting at C and proceeding upwards in the hierarchy towards the root logger.