Suppose we have this problem
public class Father{
public void method1(){...}
}
public class Child1 extends Father{
public void method1() throws Exce
If super class method does not declare an Exception then subclass overridden method can not declare checked exception. So you can only use Unchecked exception.
Other option is to allow Super class to declare ParentException and then child overridden methods can declare any exceptions which are child of ParentException