Recursion

 
class Factorial {
  // this is a recursive function
  int fact(int n) {
     int result;

    if (n == 1)
      return 1;
    result = fact(n - 1) * n;
    return result;
  }
}

public class Main {
  public static void main(String args[]) {
    Factorial f = new Factorial();

    System.out.println("Factorial of 5 is " + f.fact(5));

  }
}