code: public static VocabCache<VocabWord> readVocabCache(@NonNull File file) throws IOException {
          try (FileInputStream fis = new FileInputStream(file)) {
              return readVocabCache(fis);
          }
      }
docs: This method reads vocab cache from provided file.
  Please note: it reads only vocab content, so it's suitable mostly for BagOfWords/TF-IDF vectorizers
  
  @param file
  @return
  @throws IOException