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