Rate my Java programming skills

This is a short little program I wrote that'll find and print out all valid(passing the Luhn algorithm) credit card numbers within a range. I didn't use any existing code that's out there(although I knew I could have). Did I go about it in the best way? Does the code look okay? What could I have done differently?


import java.util.ArrayList;

public class Nir {
    
    public static ArrayList<int[]> numberSet;
    public static String number1 = "4358806222700000";
    public static String number2 = "4358806222709999";
    
    public static void main(String[] args) throws Exception {
        numberSet = new ArrayList<int[]>();
        int[] a = new int[16];
        int[] b = new int[16];
        for (int i = 15; i > -1; i--){
            a[i] = number1.charAt(i) - 48;
            b[i] = number2.charAt(i) - 48;
        }
        createList(a, b);
        for (int n = 0; n < numberSet.size(); n++){
            int[] temp = numberSet.get(n);
            for (int i = 0; i < 16; i++){
                System.out.print(temp[i]);
            }
            System.out.println();
        }
    }

    public static void createList(int[] range1, int[] range2){
        while(!equals(range1, range2)){
            if (isValid(range1)){
                int[] temp = new int[16];
                for (int i = 0; i < 16; i++){
                    temp[i] = range1[i];
                }
                numberSet.add(temp);
            }
            range1 = increment(range1);
        }
    }

    public static boolean isValid(int[] n){
        int total = 0;
        for (int i = 15; i > -1; i--){
            if (i % 2 != 0){
                total = total + n[i];
            } else {
                Integer temp = n[i] + n[i];
                int tempt = 0;
                for (int x = 0; x < temp.toString().length(); x++){
                    tempt = tempt + Integer.parseInt(String.valueOf(temp.toString().charAt(x)));
                }
                total = total + tempt;
            }
        }
        if (total % 10 == 0) {
            return true;
        } else {
            return false;
        }
    }

    public static int[] increment(int[] i){
        int[] returner = i;
        boolean finished = false;
        int s = 15;
        while (!finished){
            if (i[s] != 9){
                returner[s]++;
                finished = true;
            } else {
                returner[s] = 0;
                s--;
            }
        }
        return returner;
    }
    
    public static boolean equals(int[] range1, int[] range2){
        for (int i = 0; i < 16; i++){
            if (range1[i] != range2[i]){
                return false;
            }
        }
        return true;
    }
    
}

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Rate my Java programming skills