If I have an org.osgi.framework.Bundle object, I can ask for its localized headers (like Bundle-Name) using Bundle.getHeaders(<locale>).
But does there exist a similar facility that I can use to get the values oflocalized headers (taking the Bundle-Localization header into account, if present) when I just have a File, JarFile, or Manifest object? Or do I have to implement the whole lookup procedure myself (as outlined in the OSGi spec)?
That support is built into the OSGi framework. So if you are not asking the framework for the localized headers of a bundle, you will need to implement the specified rules yourself.