URL getPersistenceUnitRootUrl()

Returns the URL for the jar file or directory that is the root of the persistence unit. (If the persistence unit is rooted in the WEB-INF/classes directory, this is the URL of that directory.) The URL will either be a file: URL referring to a jar file or referring to a directory that contains an exploded jar file, or some other URL from which an InputStream in jar format can be obtained.