code: public int indexOf(Object o) {
  		if (o == null) {
  			for (int i = start; i < start + length; i++)
  				if (a[i] == null)
  					return i - start;
  		} else {
  			for (int i = start; i < start + length; i++)
  				if (o.equals(a[i]))
  					return i - start;
  		}
  		return -1;
  	}
docs: /*