code: public static File asFile(final File parent, final String filename) {
          final String normalized = normalizeSeparators(filename);
          return normalized != null ? new File(parent, normalized) : parent;
      }
docs: Returns a {@link File} from the given filename.
  
  Ensures that the incoming filename has backslashes converted to forward slashes (on Unix OS),
  and vice-versa on Windows OS, otherwise, the path separation methods of {@link File} will not
  work.
  
  @param parent
  parent file name
  @param filename
  filename to be used
  @return a {@link File} from the given filename.