Simple solution to the Square Challenge

main.java

package uk.microsoft;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        int size = new Scanner(System.in).nextInt();
        
        for (int i = 0; i < size; i++) {
            for (int j = 0; j < size; j++)
                System.out.print(isOnBorder(i, j, size) ? "*" : " ");
            
            System.out.println();
        }


    }

    private static boolean isOnBorder(int x, int y, int size) {
        return (x == 0 || y == 0 || x == size - 1 || y == size - 1);
    }


}