Java ArrayList add() Method

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Description

The Java ArrayList add(E e) method appends the specified element E to the end of the list. This method is used to add elements to the arraylist after its creation.

Declaration

Following is the declaration for java.util.ArrayList.add() method

public boolean add(E e)

Parameters

e − The element to be appended to this list.

Return Value

This method returns true.

Exception

NA

Java ArrayList add(index, element) Method

Description

The Java ArrayList add(int index, E element) 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).

Declaration

Following is the declaration for java.util.ArrayList.add() method

public void add(int index, E element)

Parameters

• index − The index at which the specified element is to be inserted.

• element − The element to be inserted.

Return Value

This method does not return any value.

Exception

IndexOutOfBoundsException − if the index is out of range.

Adding an Element to an ArrayList of Integers Example

The following example shows the usage of Java ArrayList add(E) method to add Integers. We're adding couple of Integers to the ArrayList object using add() method calls per element and then print each element to show the elements added.

package com.tutorialspoint;

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {
      
      // create an empty array list 
      ArrayList<Integer> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add(20);
      arrayList.add(30);
      arrayList.add(20);
      arrayList.add(30);
      arrayList.add(15);
      arrayList.add(22);
      arrayList.add(11);

      // let us print all the elements available in arrayList
      for (Integer number : arrayList) {
         System.out.println("Number = " + number);
      }
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Number = 20
Number = 30
Number = 20
Number = 30
Number = 15
Number = 22
Number = 11

Adding an Element to an ArrayList of Integers Example

The following example shows the usage of Java ArrayList add(E) method to add Strings. We're adding couple of strings to the ArrayList object using add() method calls per element and then printing the ArrayList using its toString() method.

package com.tutorialspoint;

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {
      
      // create an empty array list
      ArrayList<String> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add("Welcome");
      arrayList.add("To");
      arrayList.add("Tutorialspoint");
      System.out.println("ArrayList = " + arrayList);      
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayList = [Welcome, To, Tutorialspoint]

Adding an Element to an ArrayList of Objects Example

The following example shows the usage of Java ArrayList add(index, E) method to add Student objects at particular index. We're adding couple of Student objects to the ArrayList object using add() method calls per element and using add(index, E) in the end to add a student at particular location and then printing the ArrayList using its toString() method.

package com.tutorialspoint;

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {

      // create an empty arrayList
      ArrayList<Student> arrayList = new ArrayList<>();

      // use add() method to add elements in the arrayList
      arrayList.add(new Student(1, "Julie"));
      arrayList.add(new Student(2, "Robert"));
      arrayList.add(0, new Student(3, "Adam"));
      System.out.println("ArrayList = " + arrayList);      
   }
}

class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

ArrayList = [[ 3, Adam ], [ 1, Julie ], [ 2, Robert ]]