return lastIndexOf(elem, elementCount - 1);
if (index >= elementCount) throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);  for (int i = index; i >= 0; i--) { if (e == null ? elementData[i] == null : e.equals(elementData[i])) return i; } return -1;
  public int lastIndexOf(Object elem)  {    return lastIndexOf(elem, elementCount - 1);  }