added factorial calculation snippet

Author: Mcbencrafter

snippets/java/math/factorial.md

@@ -0,0 +1,22 @@
+---
+title: Factorial
+description: Computes the factorial of a given number
+author: Mcbencrafter
+tags: math,number,factorial
+---
+
+```java
+public static BigInteger factorial(int number) {
+    BigInteger result = BigInteger.ONE;
+
+    for (int currentNumber = 1; currentNumber <= number; currentNumber++) {
+        result = result.multiply(BigInteger.valueOf(currentNumber));
+    }
+
+    return result;
+}
+
+// Usage:
+int number = 6;
+System.out.println(factorial(number)); // 720 = 6*5*4*3*2
+```