code: public static ImmutableList<File> loadFileList(final Iterable<String> fileNames)
        throws IOException {
      final ImmutableList.Builder<File> ret = ImmutableList.builder();
  
      for (String filename : fileNames) {
        if (!filename.isEmpty()) {
          ret.add(new File(filename.trim()));
        }
      }
  
      return ret.build();
    }
docs: Takes a List of filenames and returns a list of files, ignoring any empty strings and any
  trailing whitespace.