code: public Iterator<E> iterator() {
          final Iterator<? extends E> itr = core.iterator();
          return new Iterator<E>() {
              private E last;
              public boolean hasNext() {
                  return itr.hasNext();
              }
  
              public E next() {
                  return last=itr.next();
              }
  
              public void remove() {
                  CopyOnWriteList.this.remove(last);
              }
          };
      }
docs: Returns an iterator.