code: public void sortReverse() {
      Arrays.sort(this.elements, 0, this.size);
      for (int i = 0; i < this.size / 2; i++) {
        long temp = this.elements[i];
        this.elements[i] = this.elements[this.size - i - 1];
        this.elements[this.size - i - 1] = temp;
      }
    }
docs: Sorts this vector in reverse order.