Given an array which consists of only 0, 1 and 2 sort the array without using any sorting algorithm in Java

import java.util.*;
public
class Main {
    public
    static void arrange012(int[] arr) {  // we arrange 0 1 2 iteratively
        int i = 0, j = 0, k = arr.length - 1;
        // 0 to j-1  ==> All Zeroes

        while (i <= k) {
            if (arr[i] == 0) {
                swap(arr, i, j);
                i++;
                j++;
            } else if (arr[i] == 1) {
                i++;
            } else {
                swap(arr, i, k);
                k--;
            }
        }
    }
    // used for swapping ith and jth elements of array
    public
    static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
    // main function
    public
    static void main(String[] args) throws Exception {
        Scanner scn = new Scanner(System.in);
        
        int n = 4;
        int[] arr = new int[]{ 1,0,0,1}; 
    
        arrange012(arr);
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }
    }
}