Question

Create the class Book which has the following members: 1. private members: 1. title as String 2. isbn as String 3. author as String 4. price as double 2. public members: 1. default constructor which initializes all data members to their default values. 2. non-default constructor which initializes all data members to parameters values. 3. toString which returns a representing String of the Book. 4. add all the setters and getters. Create the class EBook which is a subclass of class Book and it has the following members: 1. private members: a. downloadUrl as String b. sizeMB as double members: 2. public members: a. default constructor which initializes all data members to their default values, non- default constructor which initializes all data members to parameters values. Note: for this constructor you should call the non-default constructor in the superclass for complete you initialization. b.toString which returns a representing String of the EBook c. add all the setters and getters

Answer 1

Here in the question it was asked to create two classes Book and Ebook, where Book class extends Ebook . Hence written the source code of the two classes according to the field names specified in both the classes

SOURCE CODE:

Book.java;

package javasamples;

public class Book {
  
   private String title;// data members of Book class
   private String isbn;
   private String author;
   private double price;

public Book() // default constructor

{

}
   public Book(String title, String isbn, String author, double price)// parameterized constructor
   {
       super();
       this.title = title;
       this.isbn = isbn;
       this.author = author;
       this.price = price;
   }

// toString method as requested
   public String toString(){//overriding the toString() method
       return title+" "+isbn+" "+author+" "+price;
       }

// getters and setters
   public String getTitle() {
       return title;
   }
   public void setTitle(String title) {
       this.title = title;
   }
   public String getIsbn() {
       return isbn;
   }
   public void setIsbn(String isbn) {
       this.isbn = isbn;
   }
   public String getAuthor() {
       return author;
   }
   public void setAuthor(String author) {
       this.author = author;
   }
   public double getPrice() {
       return price;
   }
   public void setPrice(double price) {
       this.price = price;
   }

}

Ebook.java.

package javasamples;

public class Ebook extends Book{
String downloadUrl;//data members of Book class
double sizeMB;

public Ebook()//default constructor

{

}

public Ebook(String title, String isbn, String author, double price, String downloadUrl, double sizeMB)// parameterized constructor

{
   super(title, isbn, author, price);
   this.downloadUrl = downloadUrl;
   this.sizeMB = sizeMB;
}

// invoking the super class constructor
public Ebook(String title, String isbn, String author, double price) {
   super(title, isbn, author, price);
}

// getters and setters
public String getDownloadUrl() {
   return downloadUrl;
}
public void setDownloadUrl(String downloadUrl) {
   this.downloadUrl = downloadUrl;
}
public double getSizeMB() {
   return sizeMB;
}
public void setSizeMB(double sizeMB) {
   this.sizeMB = sizeMB;
}

// toString method as requested

public String toString(){//overriding the toString() method
   return downloadUrl+" "+sizeMB;
   }
}