Factorial Program in Java Using Loop and Recursion

In this tutorial, we'll learn how to calculate the factorial of a number using both loop and recursion in Java. This is one of the most common questions in Java interviews and coding challenges.

What is Factorial?

The factorial of a number n is the product of all positive integers less than or equal to n. It's represented by n!

Example:

• 5! = 5 × 4 × 3 × 2 × 1 = 120
• 3! = 3 × 2 × 1 = 6

1️⃣ Factorial Using Loop

public class FactorialLoop {
    public static void main(String[] args) {
        int number = 5;
        long fact = 1;

        for(int i = 1; i <= number; i++) {
            fact *= i;
        }

        System.out.println("Factorial of " + number + " is: " + fact);
    }
}

2️⃣ Factorial Using Recursion

public class FactorialRecursion {
    public static void main(String[] args) {
        int number = 5;
        long result = factorial(number);

        System.out.println("Factorial of " + number + " is: " + result);
    }

    static long factorial(int n) {
        if(n == 0 || n == 1)
            return 1;
        else
            return n * factorial(n - 1);
    }
}

🧠 Interview Tip

Interviewers often ask for both loop and recursive versions. Make sure you understand the stack behavior in recursion.

✅ Output

Factorial of 5 is: 120

📌 Conclusion

We have seen how to write factorial programs in Java using both loops and recursion. These examples are helpful in improving your Java logic and preparing for interviews.