AP CSA Inheritance and Polymorphism

Question 1

What keyword does a subclass use to inherit from a superclass in Java?

Accepted Answer

extends

Answer

In Java, a subclass uses the `extends` keyword to inherit fields and methods from its superclass.

Question 2

What does it mean to override a method in Java?

Accepted Answer

A subclass provides its own implementation of a method defined in the superclass

Answer

Method overriding occurs when a subclass provides a specific implementation for a method already defined in its superclass.

Question 3

What keyword is used to call the superclass constructor from a subclass constructor?

Accepted Answer

super()

Answer

The `super()` call in a subclass constructor explicitly invokes the superclass constructor to initialize inherited fields.

Question 4

Which OOP principle allows a subclass object to be used wherever a superclass reference is expected?

Accepted Answer

Polymorphism

Answer

Polymorphism allows a subclass instance to be assigned to a superclass reference variable, enabling flexible and interchangeable use.

Question 5

What is the difference between method overriding and method overloading?

Accepted Answer

Overriding redefines a superclass method; overloading defines multiple methods with the same name but different parameters

Answer

Overriding replaces a superclass method in a subclass with the same signature, while overloading creates multiple methods with the same name but different parameters in the same class.

AP CSA - Advanced Placement Computer Science A Practice Test

AP CSA - Advanced Placement Computer Science A Practice Test

AP CSA Inheritance and Polymorphism