code: public int setInt(
          @DoNotSub final int index,
          final int element)
      {
          checkIndex(index);
  
          final int previous = elements[index];
          elements[index] = element;
  
          return previous;
      }
docs: Set an element at a given index without boxing.
  
  @param index   at which to set the element.
  @param element to be added.
  @return the previous element at the index.