add
Adds the specified element element into the underlying collection immediately before the element that would be returned by next , if any, and after the element that would be returned by previous , if any. (If the collection contains no elements, the new element becomes the sole element in the collection.) The new element is inserted before the implicit cursor: a subsequent call to next would be unaffected, and a subsequent call to previous would return the new element. (This call increases by one the value that would be returned by a call to nextIndex or previousIndex .)