code: public int incrementCount (K key, int amount)
      {
          int[] val = get(key);
          if (val == null) {
              put(key, val = new int[1]);
          }
          val[0] += amount;
          return val[0];
  
          /* Alternate implementation, less hashing on the first increment but more garbage created
           * every other time.  (this whole method would be more optimal if this class were
           * rewritten)
           *
          int[] newVal = new int[] { amount };
          int[] oldVal = put(key, newVal);
          if (oldVal != null) {
              newVal[0] += oldVal[0];
              return oldVal[0];
          }
          return 0;
          */
      }
docs: Increment the value associated with the specified key, return the new value.