public class TheGreatHourglass { public static void main(String[] args) {
    int N = Integer.parseInt(args[0]);
// Input an integer using command line arguments.
// Accept all integer >= 3 printStar((2 * N) - 1);
// Trivial
nextLine();
for (int i = 1; i < N - 1; i++)
{ /* ......... Start i = 1 * * i = 1 -> 1sp, 1*, 5sp, 1*, 1sp * * i = 2 -> 2sp, 1*, 3sp, 1*, 2sp * * i = 3 -> 3sp, 1*, 1sp, 1*, 3sp . Note: Last spaces in all lines is optional . . . . . . ......... */
    printSpace(i);
} printStar();
printSpace(2 * (N - i) - 3);
printStar();
nextLine();
} printSpace(N - 1);
// Trivial
printStar();
nextLine();
for (int i = N - 2; i >= 1; i--) { /* ......... . . . . . . . Start i = 5-2 = 3. * * i = 3 -> 3sp, 1*, 1sp, 1*, 3sp * * i = 2 -> 2sp, 1*, 3sp, 1*, 2sp * * i = 1 -> 1sp, 1*, 5sp, 1*, 1sp ......... Note: Last spaces in all lines is optional. */
    printSpace(i);
}
printStar();
printSpace(2 * (N - i) - 3);
printStar();
nextLine(); }
printStar((2 * N) - 1);
// Trivial
nextLine(); }
// Template Function
// Makes it easier to understand.
private static void printSpace(int amount)
{ for (int i = 0; i < amount; i++) printSpace(); }
private static void printSpace() { System.out.print(" "); }
private static void printStar(int amount) {
for (int i = 0; i < amount; i++) printStar(); }
private static void printStar() { System.out.print("*"); }
private static void nextLine() { System.out.println(); } }