The lastIndexOf() method of java.util.AbstractList class is used to return the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element. More formally, returns the highest index i such that (o==null ? get(i)==null : o.equals(get(i))), or -1 if there is no such index.
Syntax:
public int lastIndexOf(Object o)
Parameters: This method takes Object o as a parameter which is the element to search for.
Returns Value: This method returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
Exception: This method throws NullPointerException if the specified element is null and this list does not permit null elements.
Below are the examples to illustrate the lastIndexOf() method.
Example 1:
// Java program to demonstrate// lastIndexOf() method// for String value  import java.util.*;  public class GFG1 {    public static void main(String[] argv)        throws Exception    {        try {              // Creating object of AbstractList<String>            AbstractList<String>                arrlist1 = new ArrayList<String>();              // Populating arrlist1            arrlist1.add("A");            arrlist1.add("B");            arrlist1.add("A");            arrlist1.add("B");            arrlist1.add("E");              // print arrlist1            System.out.println("ArrayList : "                               + arrlist1);              // getting the index of last occurrence            // using lastIndexOf() method            int lastindex = arrlist1.lastIndexOf("A");              // printing the Index            System.out.println("Last index of A : "                               + lastindex);        }          catch (NullPointerException e) {            System.out.println("Exception thrown : " + e);        }    }} |
ArrayList : [A, B, A, B, E] Last index of A : 2
Example 2:
// Java program to demonstrate// lastIndexOf() method// for NullPointerException  import java.util.*;  public class GFG1 {    public static void main(String[] argv)        throws Exception    {          try {              // Creating object of AbstractList<String>            AbstractList<String> arrlist1 = null;              // print arrlist1            System.out.println("ArrayList : "                               + arrlist1);              // getting the index of last occurrence            // using lastIndexOf() method            System.out.println("\nTrying to get"                               + " the index from"                               + " null ArrayList");            int lastindex = arrlist1.lastIndexOf("B");              // printing the Index            System.out.println("Last index of B : "                               + lastindex);        }          catch (NullPointerException e) {            System.out.println("Exception thrown : " + e);        }    }} |
ArrayList : null Trying to get the index from null ArrayList Exception thrown : java.lang.NullPointerException
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