To replace an element in Java ArrayList, set() method of java.util. An ArrayList class can be used. The set() method takes two parameters-the indexes of the element which has to be replaced and the new element. The index of an ArrayList is zero-based. So, to replace the first element, 0 should be the index passed as a parameter.
Declaration:
public Object set(int index, Object element)
Return Value: The element which is at the specified index
Exception Throws: IndexOutOfBoundsException
This occurs when the index is out of range.
index < 0 or index >= size()
Implementation:
Here we will be proposing out 2 examples wherein one of them we will be setting the index within bound and in the other, we will be setting the index out of bounds.
Example 1: Where Index is Within Bound
Java
// Java program to demonstrate set() Method of ArrayList// Where Index is Within Bound// Importing required classesimport java.io.*;import java.util.*;// Main classclass GFG { // Main driver method public static void main(String[] args) { // Try block to check for exceptions try { // Creating an object of Arraylist class ArrayList<String> list = new ArrayList<>(); // Adding elements to the List // using add() method // Custom input elements list.add("A"); list.add("B"); list.add("C"); list.add("D"); // Print all the elements added in the above object System.out.println(list); // 2 is the index of the element "C". //"C" will be replaced by "E" list.set(2, "E"); // Printing the newly updated List System.out.println(list); } // Catch block to handle the exceptions catch (Exception e) { // Display the exception on the console System.out.println(e); } }} |
[A, B, C, D] [A, B, E, D]
Example 2: Where Index is Out of Bound
Java
// Java program to demonstrate set() Method of ArrayList// Where Index is Out of Bound// Importing required classesimport java.io.*;import java.util.*;// Main classclass GFG { // Main driver method public static void main(String[] args) { // Try block to check for exceptions try { // Creating an object of Arraylist class ArrayList<String> list = new ArrayList<>(); // Adding elements to the List // using add() method // Custom input elements list.add("A"); list.add("B");å list.add("C"); list.add("D"); // Print all the elements added in the above object System.out.println(list); // Settijg the element at the 6 th index which // does not exist in our input list object list.set(6); // Printing the newly updated List System.out.println(list); } // Catch block to handle the exceptions catch (Exception e) { // Display the exception on the console System.out.println(e); } }} |
Output:
