ArrayList listIterator() method in Java with Examples

listIterator()

The listIterator() method of java.util.ArrayList class is used to return a list iterator over the elements in this list (in proper sequence). The returned list iterator is fail-fast.

Syntax:

public ListIterator listIterator()

Return Value: This method returns a list iterator over the elements in this list (in proper sequence).

Below are the examples to illustrate the listIterator() method.

Example 1:

// Java program to demonstrate
// listIterator() method
// for String value

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // Creating object of ArrayList<Integer>
            ArrayList<String>
                arrlist = new ArrayList<String>();

            // adding element to arrlist
            arrlist.add("A");
            arrlist.add("B");
            arrlist.add("C");
            arrlist.add("D");

            // print arrlist
            System.out.println("ArrayList: "
                               + arrlist);

            // Creating object of ListIterator<String>
            // using listIterator() method
            ListIterator<String>
                iterator = arrlist.listIterator();

            // Printing the iterated value
            System.out.println("\nUsing ListIterator:\n");
            while (iterator.hasNext()) {
                System.out.println("Value is : "
                                   + iterator.next());
            }
        }

        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

ArrayList: [A, B, C, D]

Using ListIterator:

Value is : A
Value is : B
Value is : C
Value is : D

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. An initial call to previous would return the element with the specified index minus one. The returned list iterator is fail-fast.

Syntax:

public ListIterator listIterator(int index)

Parameters: This method takes the index of the first element as a parameter to be returned from the list iterator (by a call to next)

Return Value: This method returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.

Exception: This method throws IndexOutOfBoundsException if the index is out of range (index size()).

Below are the examples to illustrate the listIterator() method.

Example 1:

// Java program to demonstrate
// listIterator() method
// for String value

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // Creating object of ArrayList<Integer>
            ArrayList<String> arrlist = new ArrayList<String>();

            // adding element to arrlist
            arrlist.add("A");
            arrlist.add("B");
            arrlist.add("C");
            arrlist.add("D");

            // print arrlist
            System.out.println("ArrayList: "
                               + arrlist);

            // getting iterated value starting from index 2
            // using listIterator() method
            ListIterator<String>
                iterator = arrlist.listIterator(2);

            // Printing the iterated value
            System.out.println("\nUsing ListIterator"
                               + " from Index 2:\n");
            while (iterator.hasNext()) {
                System.out.println("Value is : "
                                   + iterator.next());
            }
        }

        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

ArrayList: [A, B, C, D]

Using ListIterator from Index 2:

Value is : C
Value is : D

Example 2: For IndexOutOfBoundsException

// Java program to demonstrate
// listIterator() method
// for IndexOutOfBoundsException

import java.util.*;

public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {

            // Creating object of ArrayList<Integer>
            ArrayList<String>
                arrlist = new ArrayList<String>();

            // adding element to arrlist
            arrlist.add("A");
            arrlist.add("B");
            arrlist.add("C");
            arrlist.add("D");

            // print arrlist
            System.out.println("ArrayList: "
                               + arrlist);
            System.out.println("Size of ArrayList: "
                               + arrlist.size());

            // Get ListIterator from index 7
            // using listIterator() method
            System.out.println("Trying to getListIterator"
                               + " from index 7\n");

            ListIterator<String>
                iterator = arrlist.listIterator(7);
        }

        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

Output:

ArrayList: [A, B, C, D]
Size of ArrayList: 4
Trying to getListIterator from index 7

Exception thrown : java.lang.IndexOutOfBoundsException: Index: 7