Java Utility Library

Java ArrayList - add() Method

The java.util.ArrayList.add() method is used to insert the specified element at specified index in the ArrayList. The method shifts the current element at the specified position (if any) and any subsequent elements to the right by adding one to their indices. Addition of new element results into increasing the ArrayList size by one.

Syntax

public void add(int index, E element)

Here, E is the type of element maintained by the container.

Parameters

`index`	Specify index number at which new element need to be inserted in the ArrayList.
`element`	Specify element which need to be inserted in the ArrayList.

Return Value

void type.

Exception

Throws IndexOutOfBoundsException, if the index is out of range.

Example:

In the example below, the java.util.ArrayList.add() method is used to insert new element at specified position in the ArrayList.

import java.util.*;

public class MyClass {
  public static void main(String[] args) {
    //creating a ArrayList
    ArrayList<Integer> MyList = new ArrayList<Integer>();

    //populating ArrayList
    MyList.add(10);
    MyList.add(20);
    MyList.add(30);

    //inserting new element in the ArrayList
    MyList.add(1,100);
    System.out.println("MyList contains: " + MyList); 

    //inserting new element in the ArrayList
    MyList.add(0,500);
    System.out.println("MyList contains: " + MyList);    
  }
}

The output of the above code will be:

MyList contains: [10, 100, 20, 30]
MyList contains: [500, 10, 100, 20, 30]

Example:

Lets consider one more example where string elements are inserted at given position in the given ArrayList.

import java.util.*;

public class MyClass {
  public static void main(String[] args) {
    //creating a ArrayList
    ArrayList<String> MyList = 
        new ArrayList<String>();

    //populating ArrayList using add() method
    MyList.add("WED");
    MyList.add("THU");
    MyList.add("FRI");

    //displaying the content of the ArrayList
    System.out.println("MyList contains: " + MyList); 

    //inserting new element in the ArrayList
    MyList.add(0,"TUE");
    MyList.add(0,"MON");

    //displaying the content of the ArrayList
    System.out.println("MyList contains: " + MyList);  
  }
}

The output of the above code will be:

MyList contains: [WED, THU, FRI]
MyList contains: [MON, TUE, WED, THU, FRI]

❮ Java.util - ArrayList