The overriding method can throw any unchecked (runtime) exception, regardless of whether the overridden method declares the exception or not.

Yes, It can throw a RuntimeException. RuntimeException and It's childs are Unchecked Exceptions. When a parent class throws a checked exception that means overridden method, overriding method in child class it's optional to throw checked exception. If overriding method throws a checked exception that should be same as overridden or it's child. In above question it can throw a unchecked exception.