code: @Override
  	public boolean addAll(int index, Collection<? extends E> collection) {
  		int idx = getRealIndex(index);
  		return super.addAll(idx, collection);
  	}
docs: Inserts all of the elements in the specified Collection into this Vector
  at the specified position.
  
  @param index
  the index can be a positive number, or a negative number that is smaller
  than the size of the vector; see {@link #getRealIndex(int)}.
  @return
  {@code true} if this vector changed as a result of the call.
  @see
  java.util.Vector#addAll(int, java.util.Collection)