What is iterator and list iterator in Java?

An Iterator is an interface in Java and we can traverse the elements of a list in a forward direction whereas a ListIterator is an interface that extends the Iterator interface and we can traverse the elements in both forward and backward directions.

What is difference between iterator and list iterator in Java?

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 list iterator in Java?

Like Iterator, ListIterator is a Java Iterator, which is used to iterate elements one-by-one from a List implemented object. It is available since Java 1.2. It extends Iterator interface. Unlike Iterator, It supports both Forward Direction and Backward Direction iterations. …

What is the use of list iterator?

ListIterator is one of the four java cursors. It is a java iterator which is used to traverse all types of lists including ArrayList, Vector, LinkedList, Stack etc. It is available since Java 1.2. It extends the iterator interface.

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What is iterator method in Java?

An iterator is an interface that is used in place of Enumerations in the Java Collection Framework. Iterator permits the caller to remove the given elements from the specified collection during the iteration of the elements. … Method names have been enhanced.

What is MAP entrySet in Java?

entrySet() method in Java is used to create a set out of the same elements contained in the hash map. It basically returns a set view of the hash map or we can create a new set and store the map elements into them.

What is the difference between iterator and enumeration?

The main difference between Iterator and Enumeration is removal of the element while traversing the collection. Iterator can remove the element during traversal of collection as it has remove() method. Enumeration does not have remove() method.

Is iterator faster than for loop?

And for-each loop can be used only on objects implementing the iterator interface. Now back to the case of for loop and iterator. The difference comes when you try to modify a collection. In this case, iterator is more efficient because of its fail-fast property.

Can we use iterator for list?

An iterator is an object in Java that allows iterating over elements of a collection. Each element in the list can be accessed using iterator with a while loop.

Why iterator is used in Java?

Iterator in Java is used to traverse each and every element in the collection. Using it, traverse, obtain each element or you can even remove. ListIterator extends Iterator to allow bidirectional traversal of a list, and the modification of elements. The iterator() method is provided by every Collection class.

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How do you define a list iterator?

listIterator(int index)

This method used to return a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. The specified index indicates the first element that would be returned by an initial call to next.

How do you use a list iterator?

Java – How to Use Iterator?

  1. Obtain an iterator to the start of the collection by calling the collection’s iterator( ) method.
  2. Set up a loop that makes a call to hasNext( ). Have the loop iterate as long as hasNext( ) returns true.
  3. Within the loop, obtain each element by calling next( ).

What does iterator next do in Java?

‘ListIterator’ in Java is an Iterator which allows users to traverse Collection in both direction. It contains the following methods: void add(Object object): It inserts object immediately before the element that is returned by the next( ) function. … Object next( ): It returns the next element of the list.

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