Square.java

import java.util.Scanner;
import java.util.Arrays;

public class Square {

    public static  void drawSquare(int dim) {
        // Create an array with one string element to contain each row
        String arr[] = new String[dim];
        Arrays.fill(arr, "");
 
        System.out.println("Your square: ");
 
        // Populate the row strings with asterisks
        for (int i = 0; i < dim; i++) {
            // First or last row?
            if (i == 0 || i == dim-1) {
                for (int j = 0; j < dim; j++)
                    arr[i] += "* ";
            } else { // Middle rows        
                for (int k = 0; k < (dim-1)*2 + 1; k++) {
                    if (k == 0 || k == (dim-1)*2)
                        arr[i] += "*";
                    else
                        arr[i] += " ";
                }
            }
        }
        // Print out the strings
        for (int z = 0; z < arr.length; z++)
            System.out.println(arr[z]);
              
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        boolean valid = false;
        int dim = 0;

        while (!valid) {
            try {
                System.out.print("Enter " +
                    "the side length of the square to draw: ");
                dim = input.nextInt();
                valid = true;
            } catch (Exception e) {
                System.out.println("Not valid, try again.");
                input.next();
            }
        }
        drawSquare(dim);

    }

}