An array can be created to reserve space for references to objects. Using the code above, explain how an array of superclass references can hold subclass references.

Question

What will be an ideal response?

Answer 1

The Animal[] animalRef = new Animal[3]; statement reserves enough computer memory for three Animal objects named animalRef[0], animalRef[1], and animalRef[2]. The statement does not actually instantiate Animals; Animal is an abstract class and cannot be instantiated. The Animal array declaration simply reserves memory for three object references. If you instantiate objects from Animal subclasses, you can place references to those objects in the Animal array. The array of three references is used to access each appropriate speak() method.

In the AnimalArrayDemo application, a reference to an instance of the Dog class is assigned to the first Animal reference, and then references to Cow and Snake objects are assigned to the second and third array elements. After the object references are in the array, you can manipulate them like any other array elements. The application uses a for loop and a subscript to get each individual reference to speak().