Understanding Generics in the Collections Framework

As pointed out, the default classes in the Collections framework were designed to manage only references to objects of type Object. Polymorphism then permitted the use of any subclass in an implementation of any of these classes. The problem with this approach is that it is not type-safe. Look at this code fragment:

        int numberOfApples = 9;
        String orange = "Valencia";
        
        List stuff = new ArrayList();
        stuff.add(numberOfApples);
        stuff.add(orange);
        
        System.out.printf("Stuff: %s%n", stuff);

This code begins by declaring two variables...