Java Inheritance Study Questions

Questions and Answers

What is inheritance in Java?

Inheritance in Java is the technique of creating a new class by using an existing class functionality. It is a process where a child class acquires all the properties and behaviors of the parent class.

Why do we need to use inheritance or what is the purpose of using inheritance?

Inheritance is used for code reusability in Java. It helps to increase the features of a class or method by overriding and achieve runtime polymorphism.

What is Is-A relationship in Java?

Is-A relationship represents inheritance in Java and is implemented using the 'extends' keyword.

What is a superclass and subclass?

A superclass is a class from where a subclass inherits features. A subclass is a class that inherits all the members from another class. Signup and view all the answers

How is inheritance implemented or achieved in Java?

Inheritance can be achieved by using the keywords 'extends' for class-to-class inheritance and 'implements' for class-to-interface inheritance. Signup and view all the answers

What is the syntax for creating the subclass of a class?

The syntax is: class subclassName extends superclassName { // Variables and methods of subclass } Signup and view all the answers

Which class in Java is superclass of every other class?

In Java, the Object class is the superclass of every other class. Signup and view all the answers

A class can extend itself.

False Signup and view all the answers

A class can extend more than one class.

False Signup and view all the answers

Static members are inherited to subclass in Java.

True Signup and view all the answers

A final class can be extended.

False Signup and view all the answers

Can we assign a superclass to a subclass?

No. Signup and view all the answers

Are constructors inherited to subclass?

No, constructors of the superclass are not inherited to its subclass. Signup and view all the answers

Are static blocks inherited to subclass in Java?

No. Signup and view all the answers

Study Notes

Inheritance in Java

Inheritance allows the creation of a new class that utilizes the properties and behaviors of an existing class (parent class).
A child class inherits features from a parent class, enabling code reusability and reduced redundancy.

Purpose of Inheritance

Facilitates code reuse and reduces duplication.
Enables runtime polymorphism through method overriding and enhances features of a class.

Is-A Relationship

The "Is-A" relationship signifies inheritance, demonstrated by the "extends" keyword.
This relationship supports code reusability in Java.

Superclass and Subclass

Superclass: The class that provides features (also known as the base or parent class).
Subclass: A class that inherits from another class, also termed as derived, child, or extended class.

Implementing Inheritance

Achieved using the keywords "extends" (for class-to-class relationships) and "implements" (for class-to-interface relationships).

Subclass Syntax

Use the "extends" keyword to declare a subclass.

Example syntax:

class subclassName extends superclassName {
    // Variables of subclass
    // Methods of subclass
}

Object Class

The Object class is the universal superclass of all classes in Java.

Inheritance Features

Features from a superclass are inherited by a subclass but cannot be overridden.
Constructors and instance initialization blocks from the superclass are not inherited, though executed when a subclass object is created.

Constraints in Inheritance

A class cannot inherit from itself.
Superclass cannot be assigned to subclass directly.
A class can only extend one class (single inheritance); multiple inheritance is not permitted in Java.
Static methods are inherited as static members, while non-static methods are inherited as non-static members.
Final classes cannot be inherited.

Description

Explore key concepts of inheritance in Java through a set of flashcard questions. This quiz covers the definition of inheritance and its purpose in Java programming, emphasizing code reusability and class relationship. Test your understanding and get ready to enhance your Java skills!