private void validateArray(int[] array) {
    if (array == null) {
      throw new IllegalArgumentException("You can't pass a null array as argument.");
    }
  }
Second implementation for this problem. This implementation is better than the previous one
because we have reduced the complexity order of this algorithm in time terms from O(N^2) to
O(N). The complexity order in space terms is the same.
src/main/java/com/github/pedrovgs/problem12/MoveZerosInArray.java