sorting by digits

import java.util.Arrays;

public class Sort {

    private static int[] decimalToDigits(int decimal) {
        String temp = Integer.toString(decimal);
        int[] digits = new int[temp.length()];
        for (int i = 0; i < temp.length(); i++)
        {
            digits[i] = temp.charAt(i) - '0';
        }

        return digits;
    }

    private static int compareNumbers(Object o1, Object o2) {
        int i1 = (int) o1;
        int i2 = (int) o2;

        if (i1 == i2) return 0;

        int[] digits1 = decimalToDigits(i1);
        int[] digits2 = decimalToDigits(i2);

        int i;
        for (i = 0; i < digits1.length && i < digits2.length; i++) {
            if (digits1[i] == digits2[i]) {
                continue;
            }
            return digits2[i] - digits1[i];
        }

        // getting here means both numbers have the same prefix MSBs
        // need to compare first digit of smaller number with next
        // digit from larger:

        int[] larger = i1 > i2 ? digits1 : digits2;
        int[] smaller = i1 > i2 ? digits2 : digits1;

        for (int j = 0; i < larger.length && j < smaller.length; i++, j++) {
            if (larger[i] == smaller[j]) {
                continue;
            }
            return larger == digits2 ? larger[i] - smaller[j] : smaller[j] - larger[i];
        }

        // this is a case like i1 = 123, i2 = 123123. In this case,
        // both numbers can be placed first:
        return 0;
    }

    public static void main(String[] args) {
        Object[] arr = { 3, 34, 30 ,9 ,120, 345 , 345346 };

        System.out.print("Largest concatenation of numbers is: ");

        Arrays.stream(arr)
            .sorted(Sort::compareNumbers)
            .forEach(System.out::print);

        System.out.println();
    }
}