code: @Override
      public synchronized void incrementWordCount(String word, int increment) {
          if (word == null || word.isEmpty())
              throw new IllegalArgumentException("Word can't be empty or null");
          wordFrequencies.incrementCount(word, increment);
  
          if (hasToken(word)) {
              VocabWord token = tokenFor(word);
              token.increaseElementFrequency(increment);
          }
          totalWordOccurrences.set(totalWordOccurrences.get() + increment);
      }
docs: Increment the count for the given word by
  the amount increment
  
  @param word      the word to increment the count for
  @param increment the amount to increment by