Updating PR according to comment: Add throws IllegalArgumentException if payment is null.

Author: github-actions[bot]

example/PaymentDao.java

@@ -11,6 +11,7 @@ public PaymentDao(Session session) {
     /**
      * Saves payment in the database.
      * @param payment the payment to save
+     * @throws IllegalArgumentException if payment is null
      */
     public void save(Payment payment) {