java - Recursion Tutorial -

i learning java book, , come across chapter regarding recursion using factorial example.

//a simple example of recursion  package tutorials;  class factorial { // recursive method int fact (int n) {     int result;      if(n==1) return 1;     result = fact(n - 1) * n;     return result;   } }  class recursion {     public static void main(string args[]) {         factorial f = new factorial();          system.out.println("factorial of 3 " + f.fact(3));         system.out.println("factorial of 4 " + f.fact(4));         system.out.println("factorial of 5 " + f.fact(5));     } } 

the result piece of code gives "factorial of 3 6" , "factorial of 4 24"

what don't understand happening in class factorial , why *n not calculated immediately. book not job of explaining thought ask experienced programmers help.

if invoke fact(5), here how work:

fact(5)     5*fact(4)         4*fact(3)             3*fact(2)                 2*fact(1)                     2*1=2 //(since if n==1, 1 returned directly                 result=2             result=3*2         result=4*3*2     result=5*4*3*2 result=120 

recursion means invoke method within itself, after manipulating argument suit end result (n - 1 in case). make sure define terminal condition (n==1 in case). internally, variables pushed on stack remembered every invocation, that's discussion day