code: private static String toQualifiedClassName(final String fileName) {
          final String replacedSeparators = fileName.replace(File.separatorChar, '.');
          return replacedSeparators.substring(0, replacedSeparators.length() - ".class".length());
      }
docs: Converts the given file name of a class-file to the fully-qualified class name.
  
  @param fileName The file name (e.g. a/package/AClass.class)
  @return The fully-qualified class name (e.g. a.package.AClass)