Differences between Iterator and ListIterator in java

Iterator vs ListIterator

1:- Iterator is used for traversing List and Set both.

We can use ListIterator to traverse List only, we cannot traverse Set using ListIterator.

2:- We can traverse in only forward direction using Iterator.

Using ListIterator, we can traverse a List in both the directions (forward and Backward).

3:- We cannot obtain indexes while using Iterator

We can obtain indexes at any point of time while traversing a list using ListIterator. The methods nextIndex() and previousIndex() are used for this purpose.

4:- We cannot add element to collection while traversing it using Iterator, it throws ConcurrentModificationException when you try to do it.

We can add element at any point of time while traversing a list using ListIterator.

5:- We cannot replace the existing element value when using Iterator.

By using set(E e) method of ListIterator we can replace the last element returned by next() or previous() methods.

6:- Methods of Iterator:

• hasNext()
• next()
• remove()

Methods of ListIterator:

• add(E e)
• hasNext()
• hasPrevious()
• next()
• nextIndex()
• previous()
• previousIndex()
• remove()
• set(E e)

References:

Iterator javadoc
ListIterator javadoc