addAll method Null safety

void addAll (
  1. Iterable<E> iterable

Appends all objects of iterable to the end of this list.

Extends the length of the list by the number of objects in iterable. Throws an UnsupportedError if this list is fixed-length.


void addAll(Iterable<E> iterable) {
  throw new UnsupportedError("Cannot add to immutable List.");