Java application that will allow you to store details of your favourite books. Help assignment fail

[gerald hart]

Hello,

I am hoping someone can help. I am new to Java so apologies if i have made a mess of the code.

I have an assignment due and I cant get the program to work.

The individual parts work but not together. info and code below:
1.menu system
2.Ask the user how many books their application should store
3.Add book details
4.Display details of a book and Display all the Books
5.End application
Java program must have the following:
• A Book class with appropriate properties and methods (including get and set)
• Appropriate use of methods for the menu system
• Appropriate use of loops
• Appropriate use of a toString method in the Book class
• Appropriate use of validation of user entry
• Appropriate use of comments
• An application class that will run the menu described in the scenario

import java.util.Scanner;
public class CreateBookLibrary{//class


    public static void main(String[] args) {//main

        final int SIZE =5;
        String choice; //the user will enter in a specified book title
        Scanner in = new Scanner(System.in);

        String [] titles = new String[SIZE];

        for (int i=0; i<titles.length; i++){

            System.out.print("How many books would you like to store?: ");
            titles[i] = in.nextLine();
        } //for loop stop
        System.out.println();

        for(int i=0; i<titles.length; i++){

            System.out.println("Book title: "+titles[i]);

        } //for loop stop

        System.out.println();

        System.out.print("Enter the book title you want to remove: ");
        choice = in.nextLine();

        for(int i=0; i<titles.length; i++){

            if(choice.equals(titles[i])){

                titles[i] = null;
            }// if choice stop

        }// for loop stop

        System.out.println();

        System.out.println("Amended book titles");

        for(int i=0; i<titles.length; i++){

            System.out.println("Book title: "+titles[i]);

        } //end for  loop

        
        
        Book cl = new Book ("Michael Connolly", 2019, "Dennis lehane",1998);
    cl.printBookInformation();
    System.out.println("The details of the book object is "+cl.getTitle());


     Book [] book = new Book [4];//array declared to store objects(number is variable)

        //variables declared below
        String title, author,publisher;
        int yearOfPublished;

        Scanner keyboard = new Scanner(System.in);

        //User prompt to enter in details of the two books in a for loop
        for(int counter = 0; counter < book.length; counter++){

            System.out.print("Enter the title of the Book: "+(counter+1)+ ":");
            title = keyboard.nextLine();

            System.out.print("Enter the author of the Book: "+(counter+1)+ ":");
            author = keyboard.nextLine();


            System.out.print("Enter the Year of published: "+(counter+1)+":");
            yearOfPublished = keyboard.nextInt();

            System.out.print("Enter the name of the publisher"+(counter+1)+":");
            publisher = keyboard.nextLine();

            keyboard.nextLine();

            book[counter] = new Book(title, author, yearOfPublished, publisher);

            System.out.println();
        }
        for (int counter = 0; counter < book.length; counter++){
            System.out.println(" Book Details "+(counter+1)+":  ");
            book[counter].printBookInformation();

        }




    }//main

}//class

second part book class:

public class Book { //class

    // instance variables created

    private String title;
    private String author;
    private int yearOfPublish;
    private String publisher;



    public Book(String michael_connolly, int i, String dennis_lehane, int i1) {

    } // Book constructor method created to enable the user to input instance variables

    public Book (String itsTitle, String itsAuthor, int whenPublished, String publisher)
    {   this.title = itsTitle;
        this.author = itsAuthor;
        this.yearOfPublish = whenPublished;
        this.publisher = publisher;

    } //accessor method for the instance variables created above to return user input
      //get() method will allow the application class to print book details

    public String getTitle()
    {
        return title;
    }
    public String getAuthor()
    {
        return author;
    }
    public int getYear()
    {
        return yearOfPublish;
    }
    public String getPublisher()
    {
        return publisher;
    }

    // mutator method created for the instance variables- this enables the user to change the object state

    public void setTitle(String title)
    {
        this.title=title;
    }
    public void setAuthor(String author)
    {
        this.author=author;
    }
    public void setYear(int year)
    {
        this.yearOfPublish=year;
    }
    public void setPublisher(String publisher)
    {
        this.publisher=publisher;
    }

    //print code to test get() method

    void printBookInformation(){
        System.out.println(" The Title of the Book: "+title);
        System.out.println(" The Author of the Book: "+author);
        System.out.println(" Year of publish: "+yearOfPublish);
        System.out.println(" The name of the Publisher: "+publisher);
    }

    //toString method will return all of the details of the book inputted by the user

    public String toString()
    {
        return "The details of the book are: " + title + ", " + author + ", " + yearOfPublish + ", " + publisher + ", " ;
    }

} // Book class end

[Carey Brown]

gerald hart wrote:I cant get the program to work.

This doesn't help us help you. What exactly doesn't work?
Are you getting error messages? If so, post the *complete* error message.
Are you not getting the right results? If so, what input are you giving it.

[gerald hart]

Hi Carey thanks for getting back to me.

one error on the book class is saying that the method is never used. not sure how to fix it.
all i want it to do is ask user how many books to store, user inputs details and the application stores then display all books and book details.
this is what I am getting!! hope you can help

console readout:
How many books would you like to store?: 2
Enter the book title you want to remove: lehane
Amended book titles-nothing coming up

The Title of the Book:    null
The Author of the Book:   null
The Year of publish:      0
The name of the Publisher: null
The details of the book object is null

Enter the title of the Book 1: code
Enter the author of the Book 1: michael
Enter the Year of published 1:1988
Enter the name of the publisher1:obrian

then it displays book details:
Book Details 1:  

The Title of the Book:     code
The Author of the Book:    michael
The Year of publish:      1988
The name of the Publisher:
Book Details 2:  

[Knute Snortum]

It's very important that you post the exact code you are working on.  There are no unused methods in the code you posted.

There are a lot of things I could comment on but until we have the correct code, it would probably be a waste of time.

[Carey Brown]

After a quick read of your code I notice a couple of problems with your use of Scanner. You have other issues too, but this will trip you up.
           System.out.print("Enter the author of the Book: "+(counter+1)+ ":");            author = keyboard.nextLine();            System.out.print("Enter the Year of published: "+(counter+1)+":");            yearOfPublished = keyboard.nextInt();            System.out.print("Enter the name of the publisher"+(counter+1)+":");            publisher = keyboard.nextLine();            keyboard.nextLine();On line 76 you get an int, this has a side effect of leaving a pending new-line in the queue waiting to be processed. Then on line 79 you get nextLine and this sees, "ah, ha! I've got a new-line", before you've even typed anything, because it was left over from nextInt. The result is 'publlsher' is an empty String. In order to fix this you need to flush the pending new-line immediately after you call nextInt(). You do this by calling nextLine() and ignoring the returned String.

The other trap you've fallen into is that a PROJECT should only ever open a single Scanner using System.in ONCE. You are opening it twice. The best way to enforce this is to make the Scanner a constant. As a public static constant it will be available to all classes and methods in your project.

public class CreateBookLibrary {
    public static final Scanner KEYBOARD = new Scanner( System.in );
    // ...
}

Now replace all in.nextLine() with KEYBOARD.nextLine().

[Campbell Ritchie]

I would prefer to use a utility class for keyboard input. That class can hide the Scanner instance and also take care of that gotcha about nextLine(). You may not have the time to write a utility class, but if you search my posts for “Scanner utility class” you will eventually find enough parts to assemble a complete class (an one serious error).

[Knute Snortum]

Also, Carey Brown has written a KeyboardUtility (see his sig line) and I have written one called Inputer.

[Carey Brown]

FYI
I have also posted a Keyboard Scanner Utility Class, the link is in my signature at the bottom of this post.