Check if the frequency of all the digits in a number is same

// JAVA implementation using Hashmap and Collection
import java.util.*;

public class Num_balanced {
    
    public static boolean isNumBalanced(int n)
    {
        // Calling integer to char array convert function
        char[] num = num_to_arr(n);
        
        // HashMap is used to store key value pairs
        HashMap<Character, Integer> hp
            = new HashMap<Character, Integer>();
        
        // traverse char array and store array elements as
        // key and their frequency as their value
        for (int i = 0; i < num.length; i++) 
        {
            
            // if element already exists in the HashMap, so
            // we increment its previous value
            if (hp.containsKey(num[i])) 
            {
                hp.put(num[i], hp.get(num[i]) + 1);
            }
            
            // element does'nt exist in the HashMap, so we
            // initialize its value with 1
            else 
            {
                hp.put(num[i], 1);
            }
        }
        
        // use Collection to store values of all the keys
        Collection c = (Collection)hp.values();
        
        // use iterator to iterate over each value
        Iterator<?> iterator = c.iterator();
        int temp = (Integer) iterator.next();

        while (iterator.hasNext()) 
        {
            // compare each value to be equal, if not return
            // false
            if ((int) iterator.next() != temp) {
                return false;
            }
        }
        
        // each value was equal so return true
        return true;
    }
    
    // This function converts integer into char array
    public static char[] num_to_arr(int num)
    {
        // Convert integer into String
        String str = Integer.toString(num);
        char[] arr = new char[str.length()];
        
        // Insert characters of the string into char array
        for (int i = 0; i < str.length(); i++) {
            arr[i] = str.charAt(i);
        }
        return arr;
    }
   
    // Driver code
    public static void main(String[] args)
    {
        int n_1 = 1234567890;

        // Function call
        if (isNumBalanced(n_1)) 
        { 
            // if number is balanced
            System.out.println("YES");
        }
        else 
        {  
            // if number is not balanced
            System.out.println("NO");
           
        }
    }
}
// Code Contributed by YESHU GARG