Iterator vs ListIterator
1) The Iterator traverses the elements in the forward direction only.
ListIterator traverses the elements in backward and forward directions both.
2) The Iterator can be used in List, Set, and Queue.
ListIterator can be used in List only.
3) The Iterator can only perform remove operation while traversing the 
collection.
ListIterator can perform add, remove, and set operation while traversing
the collection.