### Question:
Validator { public static void validateRetryCount(int retryCount) { if (retryCount < 0) { throw new IllegalArgumentException("retryCount must be positive"); } } private  Validator(); static void validateMessage(Object message); static void validateMessageId(String messageId); static void validateRetryCount(int retryCount); static void validateDelay(long delayInMilliSecs); static void validateQueue(String queue); static void validatePriority(String priority);  }### Answer:
@Test public void validateRetryCount() { assertThrows(IllegalArgumentException.class, () -> Validator.validateRetryCount(-1)); }