What is the Difference Between Iterator and ListIterator

The major difference between Iterator and ListIterator is that Iterator can traverse the elements in the collection only in forward direction whereas, the ListIterator can traverse the elements in a collection in both the forward as well as the backwards direction.

1. Which of the following is a correct difference between the iterator and ListIterator?
2. What is the difference between iterator and enumerator?
3. What is the difference between iterator and for loop?
4. What is a ListIterator in Java?
5. Which one of the following iterator can traverse a collection in both directions?
6. What implementation of iterator can traverse a collection in both directions?
7. Which is faster enumeration or iterator?
8. Why ConcurrentHashMap is fail-safe?
9. Is iterator Fail-Safe?
10. What is the advantage of iterator over for loop?
11. What is the purpose of iterator?
12. Which is faster for or forEach Java?

Which of the following is a correct difference between the iterator and ListIterator?

listIterator(); Differences between Iterator and ListIterator: Iterator can traverse only in forward direction whereas ListIterator traverses both in forward and backward directions. ListIterator can help to replace an element whereas Iterator cannot.

What is the difference between iterator and enumerator?

The main difference between Iterator and Enumeration is that Iterator is a universal cursor, can be used for iterating any collection object. On the other hand, the Enumeration is used for traversing object of legacy class only. Enumeration object has only read-only access to the elements in the collection.

What is the difference between iterator and for loop?

The main difference between Iterator and the classic for loop, apart from the obvious one of having or not having access to the index of the item you're iterating, is that using Iterator abstracts the client code from the underlying collection implementation, allow me to elaborate.

What is a ListIterator in Java?

Like Iterator, ListIterator is a Java Iterator, which is used to iterate elements one-by-one from a List implemented object. Unlike Iterator, It supports all four operations: CRUD (CREATE, READ, UPDATE and DELETE). ... Unlike Iterator, It supports both Forward Direction and Backward Direction iterations.

Which one of the following iterator can traverse a collection in both directions?

ListIterator is an interface in a Collection framework, and it extends the Iterator interface. Using ListIterator, you can traverse the elements of the collection in both forward and backwards directions.

What implementation of iterator can traverse a collection in both directions?

On the other hand, ListIterator must be used when we want to enumerate elements of List. The object of ListIterator can be created by calling listIterator() method present in List interface. List iterator could traverses both in forward and backward directions which makes data traverse in both directions.

Which is faster enumeration or iterator?

Enumeration is used to traverse the legacy classes like Vector, Stack and HashTable. Iterator is used to iterate most of the classes in the collection framework like ArrayList, HashSet, HashMap, LinkedList etc. ... Iterator is fail-fast in nature. Enumeration is not safe and secured due to it's fail-safe nature.

Why ConcurrentHashMap is fail-safe?

util. concurrent package such as ConcurrentHashMap, CopyOnWriteArrayList, etc. are Fail-Safe in nature. ... The default iterator for the ConcurrentHashMap is weakly consistent.

Is iterator Fail-Safe?

The major difference is fail-safe iterator doesn't throw any Exception, contrary to fail-fast Iterator. This is because they work on a clone of Collection instead of the original collection and that's why they are called as the fail-safe iterator.

What is the advantage of iterator over for loop?

Iterator and for-each loop are faster than simple for loop for collections with no random access, while in collections which allows random access there is no performance change with for-each loop/for loop/iterator.

What is the purpose of iterator?

The primary purpose of an iterator is to allow a user to process every element of a container while isolating the user from the internal structure of the container. This allows the container to store elements in any manner it wishes while allowing the user to treat it as if it were a simple sequence or list.

Which is faster for or forEach Java?

for : Performance. When accessing collections, a foreach is significantly faster than the basic for loop's array access. When accessing arrays, however–at least with primitive and wrapper-arrays–access via indexes is dramatically faster.