code: public static void swap(long[] longArray, int index1, int index2) {
          XORSwap.swap(longArray, index1, longArray, index2);
      }
docs: Swap two elements of a long array at the specified positions
  
  @param longArray array that will have two of its values swapped.
  @param index1 one of the indexes of the array.
  @param index2 other index of the array.