Java

7.5    Testing Dynamic Bindings

With regard to inheritance, in a form of is-a-type-of relationship, subclasses are always also of the same type as their superclasses. The visible methods that superclasses have thus also exist in the subclasses. The advantage of specialization is that the superclass specifies a simple implementation, and a subclass can override it. We saw this specialization earlier with toString() . However, not only is specialization interesting from a design perspective but also in terms of inheritance. If a superclass provides a visible method, you always know that all subclasses will have that method, whether they override the method or not. As you’ll see in a moment, this inheritance leads to one of the most important constructs ...