In this example, why is it still necessary to typecast an object to be sure of its type, even after getClass() has been called?

Question

I\'m following this MOOC on OOP in Java and it has presented an example I don\'t fully understand. In the example, a Book class has been created and they are const

Answer 1

after

if (getClass() != object.getClass()) {
    return false;
}

you can be sure your object is a book, but java still does not know it

so you can savely tell it to try the casting with

Book compared = (Book) object;