Resources may be either base or localized. A localized
version of a base resource may be obtained
via getLocalization(Locale) .
Resource locations are used as Map keys, they must
implement hashCode() and
Resource locations are valid even if the corresponding
resource doesn't exist. To verify if a localization
actually exists, use getResourceURL() , which returns
null if the resource doesn't exist. getLocalization(Locale)
returns only real resource locations, where the resource exists.
Folders must be represented with a trailing slash.