Here are couple of rules when it comes to exceptions & method overriding.

Rule 1: If the super class method does not declare an exception, then the overriding method in the subclass cannot declare a checked exception, but can declare an unchecked exception.

Rule 2: 

(a) If the super class method declares a checked exception, then the overriding method in the subclass can declare same exception or a subclass exception or no exception at all, but cannot declare parent exception.

(b) If the super class method declares an unchecked exception, then the overriding method can declare any unchecked exception or no exception at all, but cannot declare a checked exception.