Javadoc
Searches for the property with the specified key in this property map. If the key is not found
in this property map, the parent property map, and its parents, recursively, are then checked.
If the key maps to a integer value, it will be returned as is. For string values that can be
interpreted as signed decimal integer, the respective integer value will be returned. If the
property is not found, null
will be returned. For all other types and string
values a PropertiesException will be thrown. This behaviour is intended for those usecases that
need distinguish between values that are missconfigured or not specified at all.