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Java.util.ArrayList.add() Method in Java
  • Difficulty Level : Easy
  • Last Updated : 21 Jun, 2020

Below are the add() methods of ArrayList in Java:

  1. boolean add(Object o) : This method appends the specified element to the end of this list.
    Parameters:    
    object o: The element to be appended to this list.
    Exception: NA




    // Java code to illustrate add(Object o)
    import java.io.*;
    import java.util.ArrayList;
      
    public class ArrayListDemo {
    public static void main(String[] args)
        {
      
            // create an empty array list with an initial capacity
            ArrayList<Integer> arrlist = new ArrayList<Integer>(5);
      
            // use add() method to add elements in the list
            arrlist.add(15);
            arrlist.add(20);
            arrlist.add(25);
      
            // prints all the elements available in list
            for (Integer number : arrlist) {
                System.out.println("Number = " + number);
            }
        }
    }

    Output:

    Number = 15
    Number = 20
    Number = 25
    
  2. void add(int index, Object element) : This method inserts the specified element E at the specified position in this list.It shifts the element currently at that position (if any) and any subsequent elements to the right (will add one to their indices).
    Parameters:
    index : The index at which the specified element is to be inserted.
    element : The element to be inserted.
    
    Exception:
    Throws IndexOutOfBoundsException if the specified
    index is out of range (index  size()).




    // Java code to illustrate
    // void add(int index, Object element)
    import java.io.*;
    import java.util.ArrayList;
      
    public class ArrayListDemo {
    public static void main(String[] args)
        {
      
            // create an empty array list with an initial capacity
            ArrayList<Integer> arrlist = new ArrayList<Integer>(5);
      
            // use add() method to add elements in the list
            arrlist.add(10);
            arrlist.add(22);
            arrlist.add(30);
            arrlist.add(40);
      
            // adding element 35 at fourth position
            arrlist.add(3, 35);
      
            // let us print all the elements available in list
            for (Integer number : arrlist) {
                System.out.println("Number = " + number);
            }
        }
    }

    Output:

    Number = 10
    Number = 22
    Number = 30
    Number = 35
    Number = 40
    

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