Inheritance Examples in Java: AP Computer Science A Sample Code

📚 Quick Study Guide

• 🧬 Inheritance: A mechanism where a new class (subclass/child class) inherits properties and behaviors from an existing class (superclass/parent class).
• 🔑 'extends' Keyword: Used to inherit from a class. Syntax: class Subclass extends Superclass { ... }
• 🏗️ Superclass (Parent Class): The class being inherited from.
• 🌱 Subclass (Child Class): The class that inherits from another class.
• 💡 'super' Keyword: Used to call the superclass's constructor or methods.
• 🛡️ Access Modifiers: Influence the accessibility of inherited members (private, default, protected, public).
• 🐾 Types of Inheritance: Java supports single, multilevel, and hierarchical inheritance. Multiple inheritance is achieved through interfaces.

Practice Quiz

1. Which keyword is used to implement inheritance in Java?
   1. A. implements
   2. B. inherits
   3. C. extends
   4. D. uses
2. What is the term for the class that inherits from another class?
   1. A. Superclass
   2. B. Parent class
   3. C. Subclass
   4. D. Base class
3. Which keyword is used to call the constructor of the parent class?
   1. A. this
   2. B. super
   3. C. parent
   4. D. base
4. What type of inheritance is NOT directly supported in Java classes?
   1. A. Single inheritance
   2. B. Multilevel inheritance
   3. C. Hierarchical inheritance
   4. D. Multiple inheritance
5. If a member is declared 'private' in the superclass, can it be accessed directly by the subclass?
   1. A. Yes, always
   2. B. Yes, if in the same package
   3. C. No, never
   4. D. Yes, if the subclass overrides it
6. Consider the following code:
   

   class Animal {
       public String name;
       public Animal(String name) {
           this.name = name;
       }
   }
   class Dog extends Animal {
       public Dog(String name) {
           super(name);
       }
   }

   
   What does super(name); do?
   1. A. Initializes the Dog class's name field.
   2. B. Calls the Animal class's constructor with the given name.
   3. C. Creates a new instance of the Animal class.
   4. D. Overrides the Animal class's name field.
7. Which access modifier provides the widest accessibility?
   1. A. private
   2. B. default
   3. C. protected
   4. D. public