code: public int indexOf(E e, int index) {
          Object[] elements = getArray();
          return indexOf(e, elements, index, elements.length);
      }
docs: Returns the index of the first occurrence of the specified element in
  this list, searching forwards from <tt>index</tt>, or returns -1 if
  the element is not found.
  More formally, returns the lowest index <tt>i</tt> such that
  <tt>(i&nbsp;&gt;=&nbsp;index&nbsp;&amp;&amp;&nbsp;(e==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;e.equals(get(i))))</tt>,
  or -1 if there is no such index.
  
  @param e element to search for
  @param index index to start searching from
  @return the index of the first occurrence of the element in
  this list at position <tt>index</tt> or later in the list;
  <tt>-1</tt> if the element is not found.
  @throws IndexOutOfBoundsException if the specified index is negative