What is wrong with my code for Q 7

Scanner scn = new Scanner(System.in);
int n = scn.nextInt();

	int nsp = n;
	int nst = n - 2;
	int row = 1;

	while (row <= n) {

		if (row == 1 || row == n) {
			int cst = 1;
			while (cst <= nst);
			System.out.print("*");
			cst++;
		} else {

			System.out.print("*");

			int csp = 1;
			while (csp <= nsp) {
				System.out.print(" ");
				csp++;
			}
			System.out.print("*");
		}

		System.out.println();
		row++;
		
	}