Head vs. Tail Recursive

Recursion.java

package ir.jibmib;

import java.math.BigInteger;

public class Main {

    public static void main(String[] args) {

        try{
            BigInteger result = tailRecFactorial(1000,BigInteger.valueOf(1)) ;

            System.out.println(result);
        }

        catch (Throwable exc) {

            System.out.println(exc.getMessage());
        }

    }

    private static BigInteger headRecFactorial(int n) {

        if(n == 0)
            return BigInteger.valueOf(1l);

        return BigInteger.valueOf(n).multiply(headRecFactorial(n-1));
    }

    private static BigInteger tailRecFactorial(int n, BigInteger accumulator) {

        if(n <= 1)
            return accumulator ;
        return tailRecFactorial(n-1,BigInteger.valueOf(n).multiply(accumulator));
    }
}