Factorial Tail Recursion Accumulator

FactorialTailRecursion.java

public class FactorialSum
{
  public static void main(String[] args)
  {
    Factorial myObject = new Factorial();
    
    long fact = myObject.factorial(10);
    
    System.out.print("factorial: " + fact);
  }
}

public class Factorial
{
  public long factorial(long n){
  	return factorialHelper(n, n);
  }
  public long factorialHelper(long n, long acc){
   if (n == 1) return acc;
   acc = acc * (n-1);
   return (factorialHelper(n - 1, acc));
  }
}