Question

I have a subclass and I am overriding the inherited parent method: I am removing the throws clause from the method declaration.

Now, using polymorphism, the my instance’s runtime type should determine the method implementation; yet, the compiler complains and wants a try/catch block around the method invocation when I try to compile, as if the superclass method is being invoked and not the subclass version?

I’m aware that I can remove the throws declaration or narrow down the checked exception which can be thrown when overriding. Why is this still throwing the exception?

class A{
    void foo()throws Exception{throw new Exception();}
}    

class SubB extends A{
    @Override
    void foo(){  System.out.println("B");  
}

public static void main(String[] args) {
    A a = new SubB();
    a.foo(); //compiler reports: unhandled exception type Exception 
}

Answer 1

The compiler ses an A which does throw an Exception. If you however told the compiler it’s an actual SubB object it will stop complaining

SubB b = new SubB();
b.foo();