Using Recursion
  
 Source Code
  

    
      // Contributed by - Anuj Das ( GC College, Silchar - @ Department of Computer Science )
import java.util.Scanner;

class RecursiveFactorial {
    static int findFactorial(int x) {
        if(x==0) {
            return 1;
        }
        else {
            return x * findFactorial(x-1);
        }
    }
    public static void main(String[ ] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a Number:  ");
        int x = input.nextInt();
        System.out.println("The Factorial of "+ x +" is " + findFactorial(x));
    }
}
       
    

cmd->  javac  RecursiveFactorial.java
cmd->  java  RecursiveFactorial

Enter a Number:  0
The Factorial of 0 is 1

  
Using Iteration
 Source Code

  
    // Contributed by - Anuj Das ( GC College, Silchar - @ Department of Computer Science )
import java.util.Scanner;

class IterativeFactorial {
    static int findFactorial(int x) {
    int fact = 1;
       for(int i=x; i > 0; i--) {
        fact *= i;
       }
       return fact;
     }
   
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a Number:  ");
        int x = input.nextInt();
        System.out.println("The Factorial of "+ x +" is " + findFactorial(x));
    }
 }
         

cmd->  javac  IterativeFactorial.java
cmd->  java  IterativeFactorial

Enter a Number:  5
The Factorial of 5 is 120