How to add an element to an Array in Java?

Last Updated : 30 Sep, 2019

Given an array of size n, the task is to add an element x in this array in Java.

The size of the array cannot be changed dynamically in Java, as it is done in C/C++. Hence in order to add an element in the array, one of the following methods can be done:

By creating a new array:

Create a new array of size n+1, where n is the size of the original array.
Add the n elements of the original array in this array.
Add the new element in the n+1 th position.
Print the new array.

Below is the implementation of the above approach:

// Java Program to add an element in an Array
  
import java.io.*;
import java.lang.*;
import java.util.*;
  
class GFG {
  
    // Function to add x in arr
    public static int[] addX(int n, int arr[], int x)
    {
        int i;
  
        // create a new array of size n+1
        int newarr[] = new int[n + 1];
  
        // insert the elements from
        // the old array into the new array
        // insert all elements till n
        // then insert x at n+1
        for (i = 0; i < n; i++)
            newarr[i] = arr[i];
  
        newarr[n] = x;
  
        return newarr;
    }
  
    // Driver code
    public static void main(String[] args)
    {
  
        int n = 10;
        int i;
  
        // initial array of size 10
        int arr[]
            = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  
        // print the original array
        System.out.println("Initial Array:\n"
                           + Arrays.toString(arr));
  
        // element to be added
        int x = 50;
  
        // call the method to add x in arr
        arr = addX(n, arr, x);
  
        // print the updated array
        System.out.println("\nArray with " + x
                           + " added:\n"
                           + Arrays.toString(arr));
    }
}

Output:

Initial Array:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Array with 50 added:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50]

By using ArrayList as intermediate storage:

Create an ArrayList with the original array, using asList() method.
Simply add the required element in the list using add() method
Convert the list to an array using toArray() method

// Java Program to add an element in an Array
  
import java.io.*;
import java.lang.*;
import java.util.*;
  
class GFG {
  
    // Function to add x in arr
    public static Integer[] addX(int n, Integer arr[], int x)
    {
        int i;
  
        // create a new ArrayList
        List<Integer> arrlist
            = new ArrayList<Integer>(
                Arrays.asList(arr));
  
        // Add the new element
        arrlist.add(x);
  
        // Convert the Arraylist to array
        arr = arrlist.toArray(arr);
  
        // return the array
        return arr;
    }
  
    // Driver code
    public static void main(String[] args)
    {
  
        int n = 10;
        int i;
  
        // initial array of size 10
        Integer arr[]
            = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  
        // print the original array
        System.out.println("Initial Array:\n"
                           + Arrays.toString(arr));
  
        // element to be added
        int x = 50;
  
        // call the method to add x in arr
        arr = addX(n, arr, x);
  
        // print the updated array
        System.out.println("\nArray with " + x
                           + " added:\n"
                           + Arrays.toString(arr));
    }
}

Output:

Initial Array:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Array with 50 added:
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50]

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