Java.util.ArrayList.add() Method
ArrayList add(int index, E element) method inserts the element E at the specified index. As a result, the element at that position and any subsequent elements are shifted to the right by 1 position in the List.
Syntax:
Following are the variations of the add() method.
public boolean add(E e) |
It returns true on successful insertion.
public void add(int index, E e) |
Parameters:
e – It is the element to insert to the list.
The index is the position where ‘e’ needs to be added.
Throws:
IndexOutOfBoundsException – If the index is out of range i.e (index < 0 OR index > size()).
Index starts at 0.
Example 1
This example shows how the ArrayList add() method appends the element to the end of the list.
import java.util.ArrayList;// Java code to demonstrate // the use of add()public class ArrayListDemo { public static void main(String[] args) { // create an arraylist ArrayList<integer> arrList = new ArrayList<>(); // add elements to the list, by default element // gets added to the end of the list arrList.add(10); arrList.add(20); arrList.add(30); arrList.add(40); for (Integer i : arrList) { System.out.println("Value is = " + i); } }}</integer> |
Output:
Value is = 10Value is = 20Value is = 30Value is = 40 |
Example 2
This example shows how to insert an element in between the list using add(index, element)
import java.util.ArrayList;// Demonstrate the use of add(index, element)public class ArrayListDemo { public static void main(String[] args) { // create the list ArrayList<integer> arrList = new ArrayList<>(); // insert the elements arrList.add(50); arrList.add(60); arrList.add(70); // index starts from 0, element will be added at the second position arrList.add(2, 100); for (Integer i : arrList) { System.out.println("Value is = " + i); } }}</integer> |
Output:
Value is = 50Value is = 60Value is = 100Value is = 70 |