the following java code describes a library system , i want you to find any potential exceptions that could occur and suggest improvments. /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license */ package com.mycompany.librarysystem;

import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Collection; import java.util.Date; import java.util.List; import java.util.Scanner;

/** *

• @author karamyzx */ public class LibrarySystem {

  public static void main(String[] args) { Library library = new Library(); Scanner scan = new Scanner(System.in);

   int choice;
   do {
       System.out.println("""
   Library Management System Menu:
   1. Add Student.
   2. Add Book.
   3. Loan Book.
   4. Return Book.
   5. Search Book by Title.
   6. Search Book by Author.
   7. Search Book by No.
   8. Loaned books list.
   9. Search if a book is loaned.
   10. Exit the App.
   Enter your choice: 
   """);
  
       choice = scan.nextInt();
       scan.nextLine(); // Consume the newline character.
  
       switch (choice) {
           case 1 -> {
               System.out.println("Enter the student id: ");
               int id = scan.nextInt(); //The student id input.
               scan.nextLine(); // Consume the newline character left in the input buffer after reading the integer.
  
               System.out.println("Enter the student name: ");
               String name = scan.nextLine(); //The student name input.
  
               System.out.println("Enter the student address: ");
               String address = scan.nextLine(); //The student address input.
  
               // The student birthDate input
               SimpleDateFormat birthDate = new SimpleDateFormat("dd/MM/yyyy");
               boolean validInput = false; // When the date is entered correctly, the value of this variable becomes true.
               while (!validInput) {
                   System.out.println("Enter the student birth date (in format dd/MM/yyyy): ");
                   String userInput = scan.nextLine();
                   Date parsedDate;
                   try {
                       parsedDate = birthDate.parse(userInput); //parsing the String to a Date Format.
                       System.out.println("Birth Date: " + parsedDate);
                       validInput = true;
                   } catch (ParseException e) {
                       System.out.println("Invalid date format. Please enter date in dd/MM/yyyy format.");
  
                   }
               }
  
               // The student Major input
               System.out.println("Enter the student major: ");
               String major = scan.nextLine();
  
               // Confirm adding the student
               System.out.println("Are you shure to add the student " + name
                       + "\n" + "With ID : " + id
                       + "\n" + "address: " + address
                       + "\n" + "birth date: " + birthDate
                       + "\n" + "major: " + major
                       + "\n" + "press (y) or (Y) for yes, or any another key to cancel.");
  
               String inputKey = scan.nextLine(); //The student addition confirmation Key.
  
               //Print the confirmation result
               if (inputKey.equalsIgnoreCase("Y")) {
                   System.out.println("The student " + name + " is added to the system :). ");
                   Student student = new Student(id, name, address, birthDate, major); //Create a new Student object.
                   library.addStudent(student); //Add the new student to the ArrayList students.
                   break;
               } else {
                   System.out.println("The add request is canceled");
                   break;
               }
  
           }
           //--------------------------------------------------------------------------------------------------------------
           //Book Addition
  
           case 2 -> {
               System.out.println("Enter the Book Title: ");
               String title = scan.nextLine(); //The Book title input.
  
               System.out.println("Enter the Book Genre: ");
               String genre = scan.nextLine(); //The Book genre input.
  
               System.out.println("Enter the Book Version (as a number): ");
               int version = scan.nextInt(); //The Book version input.
               scan.nextLine(); // Consume the newline character left in the input buffer after reading the String.
  
               // The student birthDate input
               SimpleDateFormat date = new SimpleDateFormat("dd/MM/yyyy");
               boolean validInput = false; // When the date is entered correctly, the value of this variable becomes true.
               while (!validInput) {
                   System.out.println("Enter the book date (in format dd/MM/yyyy): ");
                   String userInput = scan.nextLine();
                   Date parsedDate;
                   try {
                       parsedDate = date.parse(userInput); //parsing the String to a Date Format.
                       System.out.println("Parsed Date: " + parsedDate);
                       validInput = true;
                   } catch (ParseException e) {
                       System.out.println("Invalid date format. Please enter date in dd/MM/yyyy format.");
                   }
               }
  
               // The Book Author input.
               System.out.println("Enter the book author name: ");
               String authorName = scan.nextLine();
  
               Author author = new Author();
               // Checking if the Author is exists in the System.
               if (library.searchByAuthor(authorName).isEmpty()) { // Author not found
                   System.out.println("We did't found this author in our system, Please enter the rest of author data to add it to this System.");
                   System.out.println("Enter the Author address: ");
                   String authorAddress = scan.nextLine();
                   
                   // The bookAuthor birthDate input
                   SimpleDateFormat authorBirthDate = new SimpleDateFormat("dd/MM/yyyy");
                   boolean validInput2 = true; // When the date is entered correctly, the value of this variable becomes false.
                   while (validInput2) {
                       System.out.println("Enter the Author birth date (in format dd/MM/yyyy): ");
                       String userInput2 = scan.nextLine();
                       Date parsedDate2;
                       try {
                           parsedDate2 = authorBirthDate.parse(userInput2); //parsing the String to a Date Format.
                           System.out.println("Parsed Date: " + parsedDate2);
                           validInput2 = false;
                       } catch (ParseException e) {
                           System.out.println("Invalid date format. Please enter date in dd/MM/yyyy format.");
                       }
                       //Add the author.
                       author = new Author(authorName, authorAddress, authorBirthDate);
  
                   }
               } else {
                   author = library.getAuthorByName(authorName);
               }
  
               // Confirm adding the author.
               System.out.println("Are you shure to add the Book " + title
                       + "\n" + "Genre : " + genre
                       + "\n" + "Version: " + version
                       + "\n" + "Date: " + date
                       + "\n" + "Author: " + authorName
                       + "\n" + "press (y) or (Y) for yes, or any another key to cancel.");
               String inputKey = scan.nextLine(); //The Book Addition Confirmation Key.
  
               //Print the confirmation result.
               if (inputKey.equalsIgnoreCase("Y")) {
                   System.out.println("The Book " + title + " is added to the system :). ");
               } else {
                   System.out.println("The add request is canceled");
                   break;
               }
               Book book = new Book(title, author, genre, version, date); //Create a new Book object.
               library.addBook(book); //Add the new Book to the ArrayList books.
  
           }
           //--------------------------------------------------------------------------------------------------------------
           //Loan a Book.
           case 3 -> {
               int choice1;
               Book book = new Book();
               Student student = new Student();
               do {
                   System.out.println("""
                                      Please choose an option: 
                                      1-) Enter book number.
                                      2-) Enter book title.""");
                   System.out.println("Enter your choice: ");
                   choice1 = scan.nextInt();
                   scan.nextLine(); // Consume the newline character left in the input buffer after reading the integer.
  
                   switch (choice1) {
                       case 1 -> {
                           System.out.println("Please enter the book number");
                           int bookNo = scan.nextInt();
                           book = library.searchByNo(bookNo);
                           if (book == null) {
                               System.out.println("we didn't find this book!, Please retry again");
                               break;
                           }
                           break;
                       }
                       case 2 -> {
                           System.out.println("Please enter the book title: ");
                           String bookTitle = scan.nextLine();
                           book = library.searchByTitle(bookTitle);
                           if (book == null) {
                               System.out.println("we didn't find this book!, Please retry again");
                               break;
                           }
                       }
                       default -> {
                           System.out.println("Invalid option");
                           break;
                       }
                   }
               } while (choice1 < 1 || choice1 > 2);
  
               if (book.inLoan() == true) {
                   System.out.println("Sorry, This book is Loaned!");
                   break;
               }
               
               //Student input
               boolean stuValidation = false;
               while (stuValidation) {
                   System.out.println("Please enter the student ID: ");
                   int studentId = scan.nextInt();
                   student = library.findStudentById(studentId);
                   if (student == null) {
                       System.out.println("The student ID is Invalid");
                   } else {
                       stuValidation = true;
                   }
               }
  
               // Confirm Loan process.
               System.out.println("Are you sure you want to Loan the following book" + book.getTitle()
                       + "\n" + " genre: " + book.getGenre()
                       + "\n" + "Version: " + book.getVersion()
                       + "\n" + "Date: " + book.getDate()
                       + "\n" + "Author: " + book.getAuthor()
                       + "\n" + "for the student with student:" + student.getName()
                       + "\n" + " with ID:" + student.getId()
                       + "\n" + "press (y) or (Y) for yes, or any another key to cancel.");
               String inputKey = scan.nextLine(); //The Book Addition Confirmation Key.
  
               //Print the confirmation result.
               if (inputKey.equalsIgnoreCase("Y")) {
                   library.loanBook(student, book);
                   System.out.println("The Book " + book.getTitle() + " is loaned successfully :).");
               } else {
                   System.out.println("The loan request is canceled");
                   break;
               }
               break;
           }
           //--------------------------------------------------------------------------------------------------------------
           // Return Book
  
           case 4 -> {
               System.out.println("Enter the book's number to return: ");
               int bookNo = scan.nextInt();
               Book bookToReturn = library.searchByNo(bookNo);
               if (bookToReturn == null) {
                   System.out.println("Book not found!");
               } else {
                   boolean returnSuccess = library.returnBook(bookToReturn);
                   if (returnSuccess) {
                       System.out.println("Book returned successfully.");
                   } else {
                       System.out.println("Failed to return the book.");
                   }
               }
  
           }
           //--------------------------------------------------------------------------------------------------------------
           // Search Book by Title.
  
           case 5 -> {
               System.out.println("Enter book title to search: ");
               String bookTitle = scan.nextLine();
  
               Book foundBook = library.searchByTitle(bookTitle);
               if (foundBook != null) {
                   System.out.println("Book found: " + foundBook.getInfo());
               } else {
                   System.out.println("No book found with the given title.");
               }
           }
           //--------------------------------------------------------------------------------------------------------------
           // Search Book by Author.
  
           case 6 -> {
               System.out.println("Enter author's name to find their books: ");
               String authorName = scan.nextLine();
               List<Book> foundBooks = library.searchByAuthor(authorName);
               if (!foundBooks.isEmpty()) {
                   for (Book b : foundBooks) {
                       System.out.println(b.getInfo());
                   }
               } else {
                   System.out.println("No books found for the given author.");
               }
           }
           //--------------------------------------------------------------------------------------------------------------
           // Search Book by No.
  
           case 7 -> {
               System.out.println("Enter book number to search: ");
               int bookNumber = scan.nextInt();
               Book foundBook = library.searchByNo(bookNumber);
               if (foundBook != null) {
                   System.out.println("Book found: " + foundBook.getInfo());
               } else {
                   System.out.println("No book found with the given number.");
               }
           }
           //--------------------------------------------------------------------------------------------------------------
           // Loaned books list.
  
           case 8 -> {
               Collection<Loan> loans = library.getLoans();
               if (loans.isEmpty()) {
                   System.out.println("There are no loaned books at the moment.");
               } else {
                   for (Loan loan : loans) {
                       System.out.println(loan.getBook().getTitle() + " loaned by " + loan.getStudent().getName());
                   }
               }
           }
           //--------------------------------------------------------------------------------------------------------------
           // Search if a Book is Loaned.
  
           case 9 -> {
               System.out.println("Enter book title to search: ");
               String bookTitle = scan.nextLine();
  
               Book foundBook = library.searchByTitle(bookTitle);
               if (foundBook == null) {
                   System.out.println("No book found with the given title.");
               } else {
                   if (foundBook.inLoan()) {
                       System.out.println("The Book is loaned.");
                   } else {
                       System.out.println("The Book is not loaned.");
                   }
               }
           }
           //--------------------------------------------------------------------------------------------------------------
           // Exit the app.
  
           case 10 -> {
               System.out.println("Exiting... Thank you!");
           }
           default ->
               System.out.println("Invalid choice. Please enter a valid option.");
       }
  
   } while (choice != 10);

  } } /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license

• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ import java.util.ArrayList; import java.util.Collection; import java.util.List;

public class Library {

private Collection<Book> books;
private Collection<Student> students;
private Collection<Loan> loans;

public Library() {
    books = new ArrayList<>();
    students = new ArrayList<>();
    loans = new ArrayList<>();

}

// Methods for book management
public void addBook(Book book) {
    books.add(book);
}

public Book searchByNo(int number) {
    for (Book book : books) {
        if (book.getNo() == number) {
            return book;
        }
    }
    return null;
}

public Book searchByTitle(String title) {
    for (Book book : books) {
        if (book.getTitle().equalsIgnoreCase(title)) {
            return book;
        }
    }
    return null;
}

public List<Book> searchByAuthor(String authorName) {
    List<Book> foundBooks = new ArrayList<>();
    for (Book book : books) {
        if (book.getAuthor().getName().equalsIgnoreCase(authorName)) {
            foundBooks.add(book);
        }
    }
    return foundBooks;
}

// Methods for student management
public void addStudent(Student student) {
    students.add(student);
}

public Student findStudentById(int id) {
    for (Student student : students) {
        if (student.getId() == id) {
            return student;
        }
    }
    return null;
}

// Methods for loan handling
public boolean loanBook(Student student, Book book) {
    if (student.getNumLoans() < 3 && !book.inLoan()) {
        Loan loan = new Loan(book, student);
        loans.add(loan);
        book.setOnLoan(true);
        student.incrementNumLoans();
        return true;
    }
    return false;
}

public boolean returnBook(Book book) {
    for (Loan loan : loans) {
        if (loan.getBook().equals(book)) {
            loans.remove(loan);
            book.setOnLoan(false);
            loan.getStudent().decrementNumLoans();
            return true;
        }
    }
    return false;
}

// Method to check overdue loans
public List<Loan> getOverdueLoans() {
    List<Loan> overdueLoans = new ArrayList<>();
    for (Loan loan : loans) {
        if (loan.isOverdue()) {
            overdueLoans.add(loan);
        }
    }
    return overdueLoans;
}

// Getters for books, students, and loans in the library
public Collection<Book> getBooks() {
    return books;
}

public Collection<Student> getStudents() {
    return students;
}

public Collection<Loan> getLoans() {
    return loans;
}

public Author getAuthorByName(String nameToFind) {
    for (Book book : books) {
        if (book.getAuthor().getName().equalsIgnoreCase(nameToFind)) {
            return book.getAuthor(); // Found the author by name, return it
        }
    }
    return null; // Author not found
}

} /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

import java.text.SimpleDateFormat;

/** *

• @author karamyzx */ public class Book implements Display {

  private String title; private Author author; private int no; private String genre; private int version; private SimpleDateFormat date; private boolean onLoan; private static int count = 0;

  public Book() {

  }

  public Book(String title, Author author, String genre, int version, SimpleDateFormat date) { this.title = title; this.author = author; this.no = count++; this.genre = genre; this.version = version; this.date = date; this.onLoan = false; // Initially not on loan }

  public String getTitle() { return title; }

  public void setTitle(String title) { this.title = title; }

  public Author getAuthor() { return author; }

  public void setAuthor(Author author) { this.author = author; }

  public int getNo() { return no; }

  public void setNo(int no) { this.no = no; }

  public String getGenre() { return genre; }

  public void setGenre(String genre) { this.genre = genre; }

  public int getVersion() { return version; }

  public void setVersion(int version) { this.version = version; }

  public SimpleDateFormat getDate() { return date; }

  public void setDate(SimpleDateFormat date) { this.date = date; }

  public void setOnLoan(boolean onLoan) { this.onLoan = onLoan; }

  @Override public String getInfo() { return "Title: " + title + "\nAuthor: " + author.getName() + "\nNo: " + no + "\nGenre: " + genre + "\nVersion: " + version + "\nDate: " + date.toString(); }

  @Override public boolean inLoan() { return onLoan; }

} /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ import java.text.SimpleDateFormat;

public class Journal extends Book {

private int ConferenceNo;
private String ConferenceName;

public Journal(int ConferenceNo, String ConferenceName, String title, Author author, String genre, int version, SimpleDateFormat date) {
    super(title, author, genre, version, date);
    this.ConferenceNo = ConferenceNo;
    this.ConferenceName = ConferenceName;
}

public int getConferenceNo() {
    return ConferenceNo;
}

public void setConferenceNo(int ConferenceNo) {
    this.ConferenceNo = ConferenceNo;
}

public String getConferenceName() {
    return ConferenceName;
}

public void setConferenceName(String ConferenceName) {
    this.ConferenceName = ConferenceName;
}

@Override
public String toString() {
    return "Journal{" + "ConferenceNo=" + ConferenceNo + ", ConferenceName=" + ConferenceName + '}';
}

} /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ import java.text.SimpleDateFormat;

public class Magazine extends Book {

private int issueNo;
private SimpleDateFormat releaseDate;

public Magazine(int issueNo, SimpleDateFormat releaseDate, String title, Author author, String genre, int version, SimpleDateFormat date) {
    super(title, author, genre, version, date);
    this.issueNo = issueNo;
    this.releaseDate = releaseDate;
}

public int getIssueNo() {
    return issueNo;
}

public void setIssueNo(int issueNo) {
    this.issueNo = issueNo;
}

public SimpleDateFormat getReleaseDate() {
    return releaseDate;
}

public void setReleaseDate(SimpleDateFormat releaseDate) {
    this.releaseDate = releaseDate;
}

@Override
public String toString() {
    return "Magazine{" + "issueNo=" + issueNo + ", releaseDate=" + releaseDate + '}';
}

} /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ import java.text.SimpleDateFormat;

public class Author {

private int id;
private String name;
private String address;
private SimpleDateFormat birthDate;
private static int count;

public Author(String name, String address, SimpleDateFormat birthDate) {
    this.id = count++;
    this.name = name;
    this.address = address;
    this.birthDate = birthDate;
}

Author() {
}

// Getters and Setters for the Author attributes
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getAddress() {
    return address;
}

public void setAddress(String address) {
    this.address = address;
}

public SimpleDateFormat getBirthDate() {
    return birthDate;
}

public void setBirthDate(SimpleDateFormat birthDate) {
    this.birthDate = birthDate;
}

// Method to get information about the author
public String getInfo() {
    return "Author ID: " + id + "\nName: " + name + "\nAddress: " + address + "\nBirth Date: " + birthDate.toString();
}

} /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ import java.text.SimpleDateFormat;

public class Student {

private int id;
private String name;
private String address;
private SimpleDateFormat birthDate = new SimpleDateFormat("dd/MM/yyyy");
;
private String major;
private int numLoans;

public Student() {
    
}
public Student(int id, String name, String address, SimpleDateFormat birthDate, String major) {
    this.id = id;
    this.name = name;
    this.address = address;
    this.birthDate = birthDate;
    this.major = major;
    this.numLoans = 0; // Initially doesn't loan any book
}

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getAddress() {
    return address;
}

public void setAddress(String address) {
    this.address = address;
}

public SimpleDateFormat getBirthDate() {
    return birthDate;
}

public void setBirthDate(SimpleDateFormat birthDate) {
    this.birthDate = birthDate;
}

public String getMajor() {
    return major;
}

public void setMajor(String major) {
    this.major = major;
}

public void setNumLoans(int numLoans) {
    this.numLoans = numLoans;
}

public String getInfo() {
    return "Student ID: " + id + "\nName: " + name + "\nAddress: " + address
            + "\nBirth Date: " + birthDate.toString() + "\nMajor: " + major;
}

//Method to get the number of the loaned books.
public int getNumLoans() {
    return numLoans;
}

//Method to add 1 to the numLoans
public void incrementNumLoans() {
    if (numLoans < 3) {
        numLoans++;
    }
}

public void decrementNumLoans() {
    if (numLoans > 0) {
        numLoans--;
    }
}

} /*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ import java.time.LocalDate;

public class Loan {

private Book book;
private Student student;
private LocalDate dueDate;

public Loan(Book book, Student student) {
    this.book = book;
    this.student = student;
    this.dueDate = LocalDate.now().plusDays(5);
}

// Getters and Setters for the Loan attributes
public Book getBook() {
    return book;
}

public void setBook(Book book) {
    this.book = book;
}

public Student getStudent() {
    return student;
}

public void setStudent(Student student) {
    this.student = student;
}

public LocalDate getDueDate() {
    return dueDate;
}

public void setDueDate(LocalDate currentDate) {
    this.dueDate = currentDate;
}

// Method to get information about the loan
public String getInfo() {
    return "Book: " + book.getTitle() + "\nStudent: " + student.getName() + "\nDue Date: " + dueDate.toString();
}

// Method to check if the loan is overdue
public boolean isOverdue() {
    LocalDate currentDate = LocalDate.now();
    return currentDate.isAfter(dueDate);
}

}
/*

• Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
• Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Interface.java to edit this template */ package com.mycompany.librarysystem;

/** *

• @author karamyzx */ public interface Display {

  String getInfo();

  boolean inLoan(); }

fix the exceptions in the full code and write the full classes

Exceptions and Issues: {When retrieving user input, a InputMismatchException can occur if the user inputs an incorrect data type (e.g., when a String is received where an int is expected).

There is a logical error in line while (stuValidation) { which should actually be while (!stuValidation) {.

Parsing dates using SimpleDateFormat is not thread-safe, and ParseException will be thrown if the input pattern does not match.

ArrayList should be initialized in the Library class to prevent NullPointerException.

When removing a Loan from a Collection during iteration, using Collection.remove() directly inside a loop will throw ConcurrentModificationException. Iterators must be used instead.

The Book class's date field should be of type Date instead of SimpleDateFormat.

Method getInfo() in the Author and Book classes incorrectly calls toString() on SimpleDateFormat instead of formatting a Date object.

NullPointerException could occur if the author or book is not found but accessed anyway.

No check to prevent adding a null book or student to the library lists.} refer to following exceptions in java code lines.