How to add an element to an Array in Java?

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:

1. 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]
   

2. 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]