Arraylist lastIndexOf() in Java with example

The lastIndexOf() method of ArrayList in Java is used to get the index of the last occurrence of an element in an ArrayList object.

Syntax :

lastIndexOf(element)

Parameter : The element whose last index is to be returned.

Returns :
It returns the last occurrence of the element passed in the parameter. It returns -1 if the element is not found.

Program to demonstrate the working of lastIndexOf():

// Java code to demonstrate the working of
// lastIndexOf() method in ArrayList

// for ArrayList functions
import java.util.ArrayList;

public class GFG {
    public static void main(String[] args)
    {

        // creating an Empty Integer ArrayList
        ArrayList<Integer> arr = new ArrayList<Integer>(7);

        // using add() to initialize values
        arr.add(10);
        arr.add(20);
        arr.add(30);
        arr.add(40);
        arr.add(30);
        arr.add(30);
        arr.add(40);

        System.out.println("The list initially " + arr);

        // last index of 30

        int element = arr.lastIndexOf(30);
        if (element != -1)
            System.out.println("the lastIndexof of" +
                             " 30 is " + element);
        else
            System.out.println("30 is not present in" +
                                        " the list");

        // last index of 100
        element = arr.lastIndexOf(100);
        if (element != -1)
            System.out.println("the lastIndexof of 100" +
                                      " is " + element);
        else
            System.out.println("100 is not present in" +
                                           " the list");
    }
}

Output :

The list initially [10, 20, 30, 40, 30, 30, 40]
the lastIndexof of 30 is 5
100 is not present in the list