How to Replace a Element in Java ArrayList?
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:
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
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// Java program to demonstrate set[] Method of ArrayList
// Where Index is Within Bound
// Importing required classes
import java.io.*;
import java.util.*;
// Main class
class GFG {
// Main driver method
public static void main[String[] args] {
// Try block to check for exceptions
try {
// Creating an object of Arraylist class
ArrayList 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];
}
}
}
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Example 2: Where Index is Out of Bound
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// Java program to demonstrate set[] Method of ArrayList
// Where Index is Out of Bound
// Importing required classes
import java.io.*;
import java.util.*;
// Main class
class GFG {
// Main driver method
public static void main[String[] args] {
// Try block to check for exceptions
try {
// Creating an object of Arraylist class
ArrayList 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];
}
}
}
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Output: