2.4. Factorial Using Apache Commons Math
Apache Commons Math has a CombinatoricsUtils class with a static factorial method that we can use to calculate the factorial.

To include Apache Commons Math, we'll add the commons-math3 dependency into our pom:


    org.apache.commons
    commons-math3
    3.6.1

Let's see an example using the CombinatoricsUtils class:

public long factorialUsingApacheCommons(int n) {
    return CombinatoricsUtils.factorial(n);
}