Task - Collections - Finding Duplicates Using equals()

[akash-coded]

Duplicate Books in a Library

Define a class called Book.
The skeleton of the Book class is given below:

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    // parameterised constructor

    // override toString()

   // override hashCode()

   // override equals()
}

Write the implementation for hashCode() and equals() manually. (Decide which fields are important)

In the driver class, create four instances of Book class as follows:

Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);

Add the book objects to an ArrayList called library.

Print the important details of duplicate books in the list, along with a count of the number of duplicate books.

Print the details of the non-duplicate books with the highest quantity.

Expected Output:

No. of duplicate books = 1
// important fields of b1 (or b4)

// details of b2

[Gaurav-Joshi-31]

BOOK CLASS---

public class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

DRIVER CLASS---

import java.util.ArrayList;
import java.util.List;

public class BookDriver {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> list = new ArrayList<>();
        list.add(b1);
        list.add(b2);
        list.add(b3);
        list.add(b4);
        List<Book> duplicate = new ArrayList<>();
        for (int i = 0; i < list.size() - 1; i++) {
            for (int j = i + 1; j < list.size(); j++) {
                if (list.get(j).equals(list.get(i))) {
                    duplicate.add(list.get(j));
                    list.remove(j);
                    list.remove(i);

                }
            }
        }

        System.out.println("No of duplicate books  " + duplicate.size());
        duplicate.forEach(System.out::println);

        int maxIndex = 0;
        for (int i = 1; i < list.size(); i++) {
            if (list.get(i).quantity > list.get(maxIndex).quantity)
                maxIndex = i;
        }
        System.out.println(list.get(maxIndex));

    }
}

[Sarfinaa]

package week_4.collections;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public int hashCode() {
        int prime = 31;
        int result = 1;
        result = prime * result + (name == null ? 0 : name.hashCode()) + ((author == null ? 0 : author.hashCode()))
                + id;
        return result;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (id != other.id)
            return false;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

public class Books {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> library = new ArrayList<>(Arrays.asList(b1, b2, b3, b4));
        Set<Book> set = new HashSet<>();

        for (int i = 0; i < library.size(); i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(i).equals(library.get(j))) {
                    set.add(library.get(i));
                }
            }
        }
        System.out.println(String.format("No. of duplicate books = %d", set.size()));
        for (Book book : set) {
            System.out.println(book);
        }
        Book maxQuantity = null;
        int max = Integer.MIN_VALUE;
        for (Book book : library) {
            if (!set.contains(book)) {
                if (max < book.quantity) {
                    maxQuantity = book;
                    max = book.quantity;
                }
            }
        }
        System.out.println(maxQuantity);
    }
}

[Khyati-tripathi]

package CollectionModule;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

    

}

public class Employee {
    public static void main(String[] args) {

        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);
        Set<Book> duplicate = new HashSet();

        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i)))
                    duplicate.add(library.get(j));
            }
        }

        List<Book> nonDuplicate = new ArrayList<>(library);
        nonDuplicate.removeAll(duplicate);

        System.out.println("No of duplicate books: " + duplicate.size());
        duplicate.forEach(System.out::println);
        int high = 0;
        for (int i = 0; i < nonDuplicate.size(); i++) {
            if (nonDuplicate.get(i).quantity > nonDuplicate.get(high).quantity)
                high = i;
        }
        System.out.println("Highest quantity: ");
        System.out.println(nonDuplicate.get(high));

    }
}

[preeti-max]

package Collections;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

}

public class BookDriver {

    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> library = new ArrayList<>();
        Set<Book> set = new HashSet<>();

        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);
        for (int i = 0; i < library.size() - 1; i++) {
            Book a = library.get(i);
            for (int j = i + 1; j < library.size(); j++) {
                if (a.equals(library.get(j))) {
                    set.add(a);
                }

            }
        }
        System.out.println("NO of duplicates found: " + set.size());
        set.forEach(b -> System.out.println(
                "Duplicate books: +Book id: " + b.id + " Book name: " + b.name + " Book author:" + b.author));

        Book maxBook = null;
        ArrayList<Book> library2 = new ArrayList<>(library);
        library2.removeAll(set);
         int max = Integer.MIN_VALUE;
        for (Book b : library2) {

            if (b.quantity > max) {
                max = b.quantity;
                maxBook = b;

            }

        }
        System.out.println("Details of book with max quantity");
        System.out.println(maxBook);

    }

}

[ratnadeepikavuddagiri]

package JavaCollections;

import java.util.ArrayList;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;
    
    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [id=" + id + ", name=" + name + ", author=" + author + "]";
    }

    
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (this.getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (this.author == null) {
            if (other.author != null)
                return false;
        } else if (!this.author.equals(other.author))
            return false;
        if (this.id != other.id)
            return false;
        if (this.name == null) {
            if (other.name != null)
                return false;
        } else if (!this.name.equals(other.name))
            return false;
        return true;
    }

}
public class BookDriver {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        ArrayList<Book> bookList = new ArrayList<>();
        bookList.add(b1);
        bookList.add(b2);
        bookList.add(b3);
        bookList.add(b4);
        int dupCount=0;
        ArrayList<Book> duplicateList = new ArrayList<>();
        for(int i=0; i<bookList.size(); i++) {
            for(int j=i+1; j<bookList.size(); j++){
                if(bookList.get(j).equals(bookList.get(i))){
                    dupCount++;
                    duplicateList.add(bookList.get(j));
                    bookList.remove(j);
                    bookList.remove(i);
                }
            }
        }
        System.out.println("No. of duplicate books = "+dupCount);
        for(int i=0;i<duplicateList.size(); i++){
            System.out.println(duplicateList.get(i));
        }
        int maxQuantity = 0;
        Book temp=null;
        for(int i=0;i<bookList.size(); i++){
            if(bookList.get(i).quantity>maxQuantity){
                    maxQuantity = bookList.get(i).quantity;
                    temp = bookList.get(i);
            }
        }
        System.out.println(temp);
    }
}

[rakeshGit419]

import java.util.*;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;
    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }
    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null) return false;
        } else if (!author.equals(other.author)) return false;
        if (id != other.id) return false;
        if (name == null) {
            if (other.name != null) return false;
        } else if (!name.equals(other.name)) return false;
        return true;
    }

}


public class BookDriver {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> library = Arrays.asList(b1,b2,b3,b4);
        library.forEach(System.out::println);
        Set<Book> set = new HashSet<>();
        Book b5 = null;
        int maxQuant = 0;
        for(int i=0;i<library.size();i++){
            for(int j=i+1;j<library.size();j++){
                if(library.get(i).equals(library.get(j))){
                    set.add(library.get(i));
                }
            }
        }
        for(Book b : library){
            if(!set.contains(b)){
                if(b.quantity > maxQuant){
                    maxQuant = b.quantity;
                    b5 = b;
                }
            }
        }
        System.out.println("No. of duplicate books = "+set.size());
        set.forEach(System.out::println);
        System.out.println(b5);

    }
}

[KaminiJha]

package Collections;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    // parameterised constructor
    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    // override equals()
    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        } else if (other == null) {
            return false;
        } else if (this.getClass() != other.getClass())
            return false;
        Book obj = (Book) other;
        if (id != obj.id) {
            return false;
        } else {
            return this.name.equals(obj.name) && this.author.equals(obj.author)
        }
    }

    // override hashCode()
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    // override toString()
    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

}

public class BooksDriver {
    public static void main(String[] args) {

        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        // Add the book objects to an ArrayList called library.
        List<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        // Print the important details of duplicate books in the list, along with a
        // count of the number of duplicate books.
        List<Book> dups = new ArrayList<>();
        printDuplicatesDetail(library, dups);
        // // Print the details of the non-duplicate books with the highest quantity.
        printHighestQuantityBook(library, dups);
    }

    public static void printDuplicatesDetail(List<Book> library, List<Book> dups) {
        System.out.println("Priniting duplicate books");
        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(i).equals(library.get(j))) {
                    if (!dups.contains(library.get(i))) {
                        dups.add(library.get(i));
                    }
                }
            }
        }
        dups.forEach(System.out::println);
    }

    public static void printHighestQuantityBook(List<Book> library, List<Book> dups) {
        Book maxQuantityBook = null;
        int maxQuantity = Integer.MIN_VALUE;
        for (int i = 0; i < library.size(); i++) {
            Book b = library.get(i);
            if (!dups.contains(b)) {
                if (b.quantity > maxQuantity) {
                    maxQuantity = b.quantity;
                    maxQuantityBook = b;
                }
            }
        }
        System.out.println("Book with max quantity and non duplicate -->");
        System.out.println(maxQuantityBook);
    }
}

[Amrit-Raj22]

package week4.day1.day5;

import java.util.ArrayList;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    String imp() {
        return "id=" + this.id + ", name=" + this.name + ", auther=" + this.author;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        else if (!name.equals(other.name))
            return false;
        return true;
    }

    // override hashCode()

    // override equals()
}

public class DuplicateBook {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        ArrayList<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        int duplicateBook = 0;
        ArrayList<Book> duplicateList = new ArrayList<>();
        for (int i = 0; i < library.size(); i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i))) {
                    duplicateBook++;
                    duplicateList.add(library.get(j));
                    library.remove(j);
                    library.remove(i);
                }
            }
        }
        System.out.println("duplicate count:" + duplicateBook);
        for (Book b : duplicateList) {
            System.out.println("duplicate book Imp.detail:" + b.imp());
        }
        int max_q = Integer.MIN_VALUE;
        int i = 0;
        for (; i < library.size(); i++) {
            if (library.get(i).quantity > max_q) {
                max_q = library.get(i).quantity;
            }
        }
        System.out.println("max quantity:(non duplicate)" + library.get(i - 1));

    }

}

[RohitNaikade1]

import java.util.*;
class Book{
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher,int quantity){
        this.id=id;
        this.name=name;
        this.author=author;
        this.publisher=publisher;
        this.quantity=quantity;
    }

    @Override
    public String toString() {
        return "Book [id=" + id + ", name=" + name + ", author=" + author +  "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Book other = (Book) obj;
    if (author == null) {
        if (other.author != null)
            return false;
    } else if (!author.equals(other.author))
        return false;
    if (id != other.id)
        return false;
    if (name == null) {
        if (other.name != null)
            return false;
    } else if (!name.equals(other.name))
        return false;
    return true;
    }

    
}

public class FindDuplicates {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        ArrayList<Book> bookstore = new ArrayList<>();
        bookstore.add(b1);
        bookstore.add(b2);
        bookstore.add(b3);
        bookstore.add(b4);

        HashSet<Book> duplicates = new HashSet<>();

        for(int i=0;i<bookstore.size()-1;i++){
            for(int j=i+1;j<bookstore.size();j++){
                if(bookstore.get(j).equals(bookstore.get(i))){
                    duplicates.add(bookstore.get(i));
                }
            }
        }

        System.out.println("Number of Duplicates: " + duplicates.size());
        duplicates.forEach(System.out::println);

        int maxIndex=0,maxQty=0;

        for(int i=1;i<bookstore.size();i++){
            if(duplicates.contains(bookstore.get(i))){
                continue;
            }
            if(bookstore.get(i).quantity > maxQty){
                maxIndex=i;
                maxQty=bookstore.get(i).quantity;
            }
        }

        System.out.println("Max quantity Book:");
        System.out.println(bookstore.get(maxIndex));
    }
}

[Mrafe]

package week5.friday;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

}

public class BookDriver {

    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> library = new ArrayList<>();
        Set<Book> set = new HashSet<>();

        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);
        for (int i = 0; i < library.size() - 1; i++) {
            Book a = library.get(i);
            for (int j = i + 1; j < library.size(); j++) {
                if (a.equals(library.get(j))) {
                    set.add(a);
                }

            }
        }
        System.out.println("No. of duplicates found: " + set.size());
        set.forEach(System.out::println);

        Book maxBook = null;

        library.removeAll(set);
        int max = Integer.MIN_VALUE;
        for (Book b : library) {

            if (b.quantity > max) {
                max = b.quantity;
                maxBook = b;

            }

        }
        System.out.println("Book with Max quantity \n"+maxBook);

    }

}

[Batchusatyasri]

package Collectiontask;

import java.util.*;

class Book {
int id;
String name;
String author;
String publisher;
int quantity;

Book(int id, String name, String author, String publisher, int quantity) {
    this.id = id;
    this.name = name;
    this.author = author;
    this.publisher = publisher;
    this.quantity = quantity;
}

@Override
public String toString() {
    return "Book id: " + id + ", Bookname: " + name + ", Bookauthor: " + author + ", Bookpublisher: " + publisher
            + ", Bookquantity: " + quantity;
}

int count = 0;

public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((author == null) ? 0 : author.hashCode());
    result = prime * result + ((name == null) ? 0 : name.hashCode());
    return result;
}

public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (this.getClass() != obj.getClass())
        return false;
    Book other = (Book) obj;
    if (this.author == null) {
        if (other.author != null)
            return false;
    } else if (!this.author.equals(other.author))
        return false;
    if (this.id != other.id)
        return false;
    if (this.name == null) {
        if (other.name != null)
            return false;
    } else if (!this.name.equals(other.name))
        return false;
    return true;
}

}

public class Books {
public static void main(String[] args) {
int count = 0;
Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
ArrayList library = new ArrayList<>();
library.add(b1);
library.add(b2);
library.add(b3);
library.add(b4);
ArrayList dup = new ArrayList<>();
for (int i = 0; i < library.size() - 1; i++) {
for (int j = i + 1; j < library.size(); j++) {
if (library.get(j).equals(library.get(i))) {
count++;
dup.add(library.get(j));
library.remove(j);
library.remove(i);
}
}
}
System.out.println("No. of duplicate books = " + count);
for (int i = 0; i < dup.size(); i++) {
System.out.println(dup.get(i));
}
int k = 0;
Book temp = null;
for (int i = 0; i < library.size(); i++) {
if (library.get(i).quantity > k) {
k = library.get(i).quantity;
temp = library.get(i);
}
}
System.out.println(temp);
}
}

[deepak775035]

package session20;

import java.util.ArrayList;

class Book {

    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

}

public class DuplicateBookDriver {
    public static void main(String[] args) {

        ArrayList<Book> library = new ArrayList<>();

        library.add(new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8));
        library.add(new Book(233, "Operating System", "Galvin", "Wiley", 6));
        library.add(new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4));
        library.add(new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11));

        for (int i = 0; i < library.size(); i++) {

            Book currentBook = library.get(i);
            int count = 1;
            for (int j = i + 1; j < library.size(); j++) {
                if (currentBook.equals(library.get(j))) {
                    count++;
                    library.remove(j);
                }
            }

            if (count != 1) {
                System.out.println("No. of duplicate books =" + count);
                System.out.println(currentBook);
                library.remove(i);
            }
        }

        System.out.println("\n\nUnique Highest quantity:");
        Book highestQuantityBook = null;
        for (Book book : library) {
            if (highestQuantityBook == null || highestQuantityBook.quantity < book.quantity)
                highestQuantityBook = book;
        }
        System.out.println(highestQuantityBook);

    }
}

[GantaGreeshma]

package collection_framework;

import java.util.*;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public boolean equals(Object book) {
        if (book == null) {
            return false;
        }
        if (this == null) {
            return false;
        }
        if (getClass() != book.getClass()) {
            return false;
        }
        Book obj = (Book) book;
        if (author == null) {
            if (obj.author != null) {
                return false;
            }
        } else if (author != obj.author) {
            return false;
        }
        if (id != obj.id) {
            return false;
        }
        if (name == null) {
            if (obj.name != null) {
                return false;
            }
        } else if (name != obj.name) {
            return false;
        }
        return true;
    }

    @Override
    public int hashCode() {
        int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

}

public class DublicateBooks {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> list = new ArrayList<>();
        list.add(b1);
        list.add(b2);
        list.add(b3);
        list.add(b4);
        List<Book> dupe = new ArrayList<>();
        for (int i = 0; i < list.size() - 1; i++) {
            for (int j = i + 1; j < list.size(); j++) {
                if (list.get(j).equals(list.get(i))) {
                    dupe.add(list.get(j));
                }

            }
        }
        System.out.println("number of dublicates :" + dupe.size());
        dupe.forEach(System.out::println);
        list.removeAll(dupe);
        int max = 0;
        for (int i = 0; i < list.size(); i++) {
            if (!(dupe.contains(list.get(i)))) {
                if (list.get(i).quantity > list.get(max).quantity) {
                    max = i;
                }
            }
        }
        System.out.println(list.get(max));
    }
}

[nithin1429]

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Book {
int id;
String name;
String author;
String publisher;
int quantity;

public Book(int id, String name, String author, String publisher, int quantity) {
    this.id = id;
    this.name = name;
    this.author = author;
    this.publisher = publisher;
    this.quantity = quantity;
}

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((author == null) ? 0 : author.hashCode());
    result = prime * result + id;
    result = prime * result + ((name == null) ? 0 : name.hashCode());
    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Book other = (Book) obj;
    if (author == null) {
        if (other.author != null)
            return false;
    } else if (!author.equals(other.author))
        return false;
    if (id != other.id)
        return false;
    if (name == null) {
        if (other.name != null)
            return false;
    } else if (!name.equals(other.name))
        return false;
    return true;
}

@Override
public String toString() {
    return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
            + quantity + "]";
}

}

public class BookCount {

public static void main(String[] args) {
    Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
    Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
    Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
    Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
    List<Book> library = new ArrayList<>();
    Set<Book> set = new HashSet<>();

    library.add(b1);
    library.add(b2);
    library.add(b3);
    library.add(b4);
    for (int i = 0; i < library.size() - 1; i++) {
        Book a = library.get(i);
        for (int j = i + 1; j < library.size(); j++) {
            if (a.equals(library.get(j))) {
                set.add(a);
            }

        }
    }
    System.out.println("NO of duplicates found: " + set.size());
    set.forEach(b -> System.out.println(
            "Duplicate books: +Book id: " + b.id + " Book name: " + b.name + " Book author:" + b.author));

    Book maxBook = null;

    library.removeAll(set);
    int max = Integer.MIN_VALUE;
    for (Book b : library) {

        if (b.quantity > max) {
            max = b.quantity;
            maxBook = b;

        }

    }
    System.out.println("Details of book with max quantity");
    System.out.println(maxBook);

}

}

[sruthi-15-sketch]

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

class BookArrayList {
    public static void main(String[] args) {
        ArrayList<Book> library = new ArrayList<>();
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);
        ArrayList<Book> duplicate = new ArrayList<>();
        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i))) {
                    duplicate.add(library.get(j));
                }
            }
        }
        library.removeAll(duplicate);
        System.out.println("No of duplicate books: " + duplicate.size());
        duplicate.forEach(System.out::println);
        // library.forEach(System.out::println);
        int max_quantity = 0;
        for (int i = 0; i < library.size() - 1; i++) {
            if (library.get(i).quantity > library.get(i + 1).quantity) {
                max_quantity = i;
            }
        }
        System.out.println("Non-duplicate books with the highest quantity " + library.get(max_quantity));
    }
}```

[Shubhi27]

package collections;

import java.util.ArrayList;
import java.util.List;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

public class BookDriver {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> book = new ArrayList<Book>();
        book.add(b1);
        book.add(b2);
        book.add(b3);
        book.add(b4);

        List<Book> mylist = new ArrayList<>();
        mylist.add(b1);
        mylist.add(b2);
        mylist.add(b3);
        mylist.add(b4);
        List<Book> duplicate = new ArrayList<>();
        for (int i = 0; i < mylist.size() - 1; i++) {
            for (int j = i + 1; j < mylist.size(); j++) {
                if (mylist.get(j).equals(mylist.get(i))) {
                    duplicate.add(mylist.get(j));
                    mylist.remove(j);
                    mylist.remove(i);

                }
            }
        }

        System.out.println("duplicate books are:  " + duplicate.size());
        duplicate.forEach(System.out::println);

        int maxQuantity = 0;
        for (int i = 1; i < mylist.size(); i++) {
            if (mylist.get(i).quantity > mylist.get(maxQuantity).quantity)
                maxQuantity = i;
        }
        System.out.println(mylist.get(maxQuantity));
    }
}

[Harshita-Joshi]

package collections;

import java.util.ArrayList;
import java.util.*;

class Book{

    int id;
    String name;
    String author;
    String publisher;
    int quantity;
    
    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

   

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        
        return true;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

}

public class BookDriver {
    public static void main(String[] args) {
        
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);

        List<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        List<Book> dup = new ArrayList<>();

        for(int i=0; i<library.size()-1; i++){
            for(int j=i+1; j<library.size(); j++){
                if(library.get(j).equals(library.get(i))){
                    dup.add(library.get(j));
                    library.remove(j);
                    library.remove(i);
                }
            }
        }

        System.out.println("Found "+ dup.size()+" duplicate(s)");
        System.out.println("Duplicate details: ");
        for(int i=0; i<dup.size(); i++){
            System.out.println(dup.get(i));
        }

        int maxQuantIndex = 0;
        for(int i=1; i<library.size(); i++){
            if(library.get(i).quantity > library.get(maxQuantIndex).quantity){
                maxQuantIndex = i;
            }
        }

        System.out.println("Non duplicate book with highest quantity");
        System.out.println(library.get(maxQuantIndex));



    }
}

[ShraddhaPenshanwar]

public class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}
DRIVER CLASS---

import java.util.ArrayList;
import java.util.List;

public class BookDriver {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> list = new ArrayList<>();
        list.add(b1);
        list.add(b2);
        list.add(b3);
        list.add(b4);
        List<Book> duplicate = new ArrayList<>();
        for (int i = 0; i < list.size() - 1; i++) {
            for (int j = i + 1; j < list.size(); j++) {
                if (list.get(j).equals(list.get(i))) {
                    duplicate.add(list.get(j));
                    list.remove(j);
                    list.remove(i);

                }
            }
        }

        System.out.println("No of duplicate books  " + duplicate.size());
        duplicate.forEach(System.out::println);

        int maxIndex = 0;
        for (int i = 1; i < list.size(); i++) {
            if (list.get(i).quantity > list.get(maxIndex).quantity)
                maxIndex = i;
        }
        System.out.println(list.get(maxIndex));

    }
}````

[shreiyarandive]

import java.util.*;
class Book{
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher,int quantity){
        this.id=id;
        this.name=name;
        this.author=author;
        this.publisher=publisher;
        this.quantity=quantity;
    }

    @Override
    public String toString() {
        return "Book [id=" + id + ", name=" + name + ", author=" + author +  "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Book other = (Book) obj;
    if (author == null) {
        if (other.author != null)
            return false;
    } else if (!author.equals(other.author))
        return false;
    if (id != other.id)
        return false;
    if (name == null) {
        if (other.name != null)
            return false;
    } else if (!name.equals(other.name))
        return false;
    return true;
    }

    
}

public class FindDuplicates {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        ArrayList<Book> bookstore = new ArrayList<>();
        bookstore.add(b1);
        bookstore.add(b2);
        bookstore.add(b3);
        bookstore.add(b4);

        HashSet<Book> duplicates = new HashSet<>();

        for(int i=0;i<bookstore.size()-1;i++){
            for(int j=i+1;j<bookstore.size();j++){
                if(bookstore.get(j).equals(bookstore.get(i))){
                    duplicates.add(bookstore.get(i));
                }
            }
        }

        System.out.println("Number of Duplicates: " + duplicates.size());
        duplicates.forEach(System.out::println);

        int maxIndex=0,maxQty=0;

        for(int i=1;i<bookstore.size();i++){
            if(duplicates.contains(bookstore.get(i))){
                continue;
            }
            if(bookstore.get(i).quantity > maxQty){
                maxIndex=i;
                maxQty=bookstore.get(i).quantity;
            }
        }

        System.out.println("Max quantity Book:");
        System.out.println(bookstore.get(maxIndex));
    }
}

[DivikaAgrawal]

package exception_handing.Collections;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.Collections;
import java.util.List;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

}

public class Library {
    public static void main(String[] args) {

        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);

        List<Book> booklist = new ArrayList<>();
        booklist.add(b1);
        booklist.add(b2);
        booklist.add(b3);
        booklist.add(b4);

        Set<Book> duplicatebook = new HashSet<>();

        for (int i = 0; i < booklist.size(); i++) {
            for (int j = i + 1; j < booklist.size(); j++) {
                if (booklist.get(i).equals(booklist.get(j)))
                    duplicatebook.add(booklist.get(i));
            }
        }

        System.out.println("No of duplicate books =" + duplicatebook.size());
        duplicatebook.forEach(System.out::println);

        List<Book> nonduplicatebook = new ArrayList<>(booklist);
        nonduplicatebook.removeAll(duplicatebook);

        int max = 0;
        int temp = 0;
        for (int i = 0; i < nonduplicatebook.size(); i++) {
            if (nonduplicatebook.get(i).quantity > max) {
                max = nonduplicatebook.get(i).quantity;
                temp = i;
            }
        }

        System.out.println("Maximum=" + max);
        System.out.println(nonduplicatebook.get(temp));

    }
}

[Snehil6197]

import java.util.ArrayList;
import java.util.*;

class Book {
int id;
String name;
String author;
String publisher;
int quantity;

Book(int id, String name, String author, String publisher, int qty) {
    this.id = id;
    this.name = name;
    this.author = author;
    this.publisher = publisher;
    this.quantity = qty;
}

@Override
public String toString() {
    return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
            + quantity + "]";
}

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + id;
    result = result + ((name == null) ? 0 : name.hashCode());
    result = result + ((author == null) ? 0 : author.hashCode());
    return result;
}

@Override
public boolean equals(final Object other) {
    if (this == other) {
        return true;
    }
    if (other == null) {
        return false;
    }
    Book b = (Book) other;
    if (this.id != b.id) {
        return false;
    }
    if (this.getClass() != b.getClass()) {
        return false;
    }
    if ((this.name == null && b.name == null) && (this.author == null && b.author == null)) {
        return true;
    }

    if ((this.name.equals(b.name)) && (this.author.equals(b.author))) {
        return true;
    }
    return false;
}

}

public class DuplicateBooks {
public static void main(String[] args) {
List books = new ArrayList<>();
List indx = new ArrayList<>();
Set duplicate = new HashSet<>();
List nonDuplicateBooks = new ArrayList<>();
int count = 0;
Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
Book b5 = new Book(121, "Let us C", "Yashwant Kanetkar", "snehilpub", 8);
books.add(b1);
books.add(b2);
books.add(b3);
books.add(b4);
books.add(b5);
nonDuplicateBooks.addAll(books);
for (int i = 0; i < books.size() - 1; i++) {
for (int j = i + 1; j < books.size(); j++) {
if (books.get(i).equals(books.get(j))) {
count += 1;
nonDuplicateBooks.remove(books.get(i));
nonDuplicateBooks.remove(books.get(j));
duplicate.add(books.get(i));
duplicate.add(books.get(j));
}
}
}
System.out.println("duplicate book count is : " + count);
duplicate.forEach(System.out::println);
int maxIndex = 0;
for (int i = 1; i < nonDuplicateBooks.size(); i++) {
if (nonDuplicateBooks.get(i).quantity > nonDuplicateBooks.get(maxIndex).quantity)
maxIndex = i;
}
System.out.println(nonDuplicateBooks.get(maxIndex));
}

}

``

[lalit-ky]

package collections;

import java.util.ArrayList;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

public class BookDriver {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        ArrayList<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        ArrayList<Book> duplicate = new ArrayList<>();
        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(i).equals(library.get(j))) {
                    duplicate.add(library.get(i));
                    library.remove(j);
                    library.remove(i);
                }
            }
        }
        System.out.println("No of duplicate books = " + duplicate.size());
        duplicate.forEach(System.out::println);

        int index = 0;
        for (int i = 1; i < library.size(); i++) {
            if (library.get(i).quantity > library.get(index).quantity) {
                index = i;
            }
        }
        System.out.println("\n" + library.get(index));
    }
}

[Prem-3]

`
import java.util.*;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class Book1 {
int id;
String name;
String author;
String publisher;
int quantity;

public Book1(int id, String name, String author, String publisher, int quantity) {
    this.id = id;
    this.name = name;
    this.author = author;
    this.publisher = publisher;
    this.quantity = quantity;
}

@Override
public String toString() {
    return "Book1 [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
            + quantity + "]";
}

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((author == null) ? 0 : author.hashCode());
    result = prime * result + id;
    result = prime * result + ((name == null) ? 0 : name.hashCode());
    result = prime * result + ((publisher == null) ? 0 : publisher.hashCode());
    result = prime * result + quantity;
    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Book1 other = (Book1) obj;
    if (author == null) {
        if (other.author != null)
            return false;
    } else if (!author.equals(other.author))
        return false;
    if (id != other.id)
        return false;
    if (name == null) {
        if (other.name != null)
            return false;
    } else if (!name.equals(other.name))
        return false;
    if (publisher == null) {
        if (other.publisher != null)
            return false;
    } else if (!publisher.equals(other.publisher))
        return false;
    if (quantity != other.quantity)
        return false;
    return true;
}

}

public class BookDriver {
public static void main(String[] args) {
Book1 b1 = new Book1(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
Book1 b2 = new Book1(233, "Operating System", "Galvin", "Wiley", 6);
Book1 b3 = new Book1(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
Book1 b4 = new Book1(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
List library = new ArrayList<>();
library.add(b1);
library.add(b2);
library.add(b3);
library.add(b4);
Set set = new HashSet<>();
for (int i = 0; i < library.size() - 1; i++) {
Book1 a = library.get(i);
for (int j = i + 1; j < library.size(); j++) {
if (a.equals(library.get(j))) {
set.add(a);
}

        }
    }
    System.out.println("No. of duplicates found: " + set.size());
    set.forEach(System.out::println);

    Book1 maxBook = null;

    library.removeAll(set);
    int max = Integer.MIN_VALUE;
    for (Book1 b : library) {

        if (b.quantity > max) {
            max = b.quantity;
            maxBook = b;

        }

    }
    System.out.println("Book with Max quantity \n" + maxBook);

}

}

`

[ghost]

import java.util.*;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((publisher == null) ? 0 : publisher.hashCode());
        result = prime * result + quantity;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (publisher == null) {
            if (other.publisher != null)
                return false;
        } else if (!publisher.equals(other.publisher))
            return false;
        if (quantity != other.quantity)
            return false;
        return true;
    }

    // override toString()

    // override hashCode()

    // override equals()
}

public class Main {

    public static void main(String[] args) {

        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        List<Book> duplicate = new ArrayList<>();

        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i))) {
                    duplicate.add(library.get(j));

                }
            }
        }

        System.out.println("No of duplicate books  " + duplicate.size());
        duplicate.forEach(System.out::println);
        int maxquan = 0;
        for (int i = 0; i < library.size(); i++) {
            if (library.get(i).quantity > library.get(maxquan).quantity) {
                maxquan = i;
            }
        }
        System.out.println("");
        System.out.printf("Maximum quantity of a book is: " + library.get(maxquan));

    }

}

[gayatribabar]

import java.util.List;
import java.util.ArrayList;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    // parameterised constructor
    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

}

public class Discussion46 {
    public static void main(String[] args) {

        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);

        List<Book> Library = new ArrayList<>();
        Library.add(b1);
        Library.add(b2);
        Library.add(b3);
        Library.add(b4);

        for (int i = 0; i < Library.size(); i++) {
            for (int j = i + 1; j < Library.size(); j++) {
                if (Library.get(i).equals(Library.get(j))) {
                    System.out.println(Library.get(i) + "\n" + Library.get(j) + "\n");
                    if (Library.get(i).quantity > Library.get(j).quantity) {
                        System.out.println("Duplicate book with highest quantity: \n" + Library.get(i));
                    } else if (Library.get(i).quantity < Library.get(j).quantity) {
                        System.out.println("Duplicate book with highest quantity: \n" + Library.get(j));
                    }
                }

            }
        }

    }
}

[Coder-093]

import java.util.*;

public class task46 {
  public static void main(String[] args) {
    Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
    Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
    Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
    Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);

    ArrayList<Book> library = new ArrayList<Book>();

    library.add(b1);
    library.add(b2);
    library.add(b3);
    library.add(b4);

    ArrayList<Book> library2 = new ArrayList<Book>();

    for (int i = 0; i < library.size() - 1; i++) {
      for (int j = i + 1; j < library.size(); j++) {
        if (library.get(i).equals(library.get(j))) {
          library2.add(library.get(i));
        }
      }
    }
    System.out.println("quantity of duplicate books = " + library2.size());
    library2.forEach(System.out::println);
    System.out.println();

    int qmax = 0;
    for (int i = 0; i < library.size(); i++) {
      if (library.get(i).quantity > library.get(qmax).quantity) {
        qmax = i;
      }
    }
    System.out.println("quantity of non-duplicate books = " + qmax);
    library.forEach(System.out::println);
    System.out.println();
  }
}

class Book {
  int id;
  String name;
  String author;
  String publisher;
  int quantity;

  public Book(int id, String name, String author, String publisher, int quantity) {
    this.id = id;
    this.name = name;
    this.author = author;
    this.publisher = publisher;
    this.quantity = quantity;
  }

  @Override
  public String toString() {
    return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
        + quantity + "]";
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((author == null) ? 0 : author.hashCode());
    result = prime * result + id;
    result = prime * result + ((name == null) ? 0 : name.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    Book other = (Book) obj;
    if (author == null) {
      if (other.author != null)
        return false;
    } else if (!author.equals(other.author))
      return false;
    if (id != other.id)
      return false;
    if (name == null) {
      if (other.name != null)
        return false;
    } else if (!name.equals(other.name))
      return false;
    return true;
  }

}

[ghost]

import java.util.ArrayList;

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    String imp() {
        return "id=" + this.id + ", name=" + this.name + ", auther=" + this.author;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        else if (!name.equals(other.name))
            return false;
        return true;
    }
}

public class d46 {
    public static void main(String[] args) {
        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        ArrayList<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        int duplicateBook = 0;
        ArrayList<Book> duplicateList = new ArrayList<>();
        for (int i = 0; i < library.size(); i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i))) {
                    duplicateBook++;
                    duplicateList.add(library.get(j));
                    library.remove(j);
                    library.remove(i);
                }
            }
        }
        System.out.println("duplicate count:" + duplicateBook);
        for (Book b : duplicateList) {
            System.out.println("duplicate book Imp.detail:" + b.imp());
        }
        int max_q = Integer.MIN_VALUE;
        int i = 0;
        for (; i < library.size(); i++) {
            if (library.get(i).quantity > max_q) {
                max_q = library.get(i).quantity;
            }
        }
        System.out.println("max quantity:(non duplicate)" + library.get(i - 1));
    }
}

[vshvandana]

import java.util.ArrayList;
import java.util.List;

class book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return "book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((author == null) ? 0 : author.hashCode());
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((publisher == null) ? 0 : publisher.hashCode());
        result = prime * result + quantity;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        book other = (book) obj;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (publisher == null) {
            if (other.publisher != null)
                return false;
        } else if (!publisher.equals(other.publisher))
            return false;
        if (quantity != other.quantity)
            return false;
        return true;
    }

}

public class books {
    public static void main(String[] args) {
        book b1 = new book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        book b2 = new book(233, "Operating System", "Galvin", "Wiley", 6);
        book b3 = new book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        book b4 = new book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
        List<book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);
        List<book> duplicate = new ArrayList<>();
        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i))) {
                    duplicate.add(library.get(j));
                    library.remove(j);
                    library.remove(i);

                }
            }
        }

        System.out.println("No of duplicate books  " + duplicate.size());
        duplicate.forEach(System.out::println);

        int max = 0;
        for (int i = 1; i < library.size(); i++) {
            if (library.get(i).quantity > library.get(max).quantity)
                max = i;
        }
        System.out.println(library.get(max));

    }
}

[meghvi-raj]

import java.util.ArrayList;
import java.util.List;

public class D46 {

    public static void main(String[] args) {

        Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
        Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);

        List<Book> library = new ArrayList<>();
        library.add(b1);
        library.add(b2);
        library.add(b3);
        library.add(b4);

        List<Book> duplicate = new ArrayList<>();

        for (int i = 0; i < library.size() - 1; i++) {
            for (int j = i + 1; j < library.size(); j++) {
                if (library.get(j).equals(library.get(i))) {
                    duplicate.add(library.get(j));
                    library.remove(j);
                    library.remove(i);

                }
            }
        }

        System.out.println("No of duplicate books  " + duplicate.size());
        duplicate.forEach(System.out::println);

        int maxIndex = 0;
        for (int i = 1; i < library.size(); i++) {
            if (library.get(i).quantity > library.get(maxIndex).quantity)
                maxIndex = i;
        }
        System.out.println("Non duplicate book of highest quantity: " + library.get(maxIndex));
    }

}

class Book {
    int id;
    String name;
    String author;
    String publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }

    @Override
    public int hashCode() {
        int prime = 31;
        int result = 1;
        result = prime * result + (name == null ? 0 : name.hashCode()) + ((author == null ? 0 : author.hashCode()))
                + id;
        return result;
    }

    @Override
    public String toString() {
        return "Book [author=" + author + ", id=" + id + ", name=" + name + ", publisher=" + publisher + ", quantity="
                + quantity + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Book other = (Book) obj;
        if (id != other.id)
            return false;
        if (author == null) {
            if (other.author != null)
                return false;
        } else if (!author.equals(other.author))
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}

[NavneetBais]

Book

import java.util.Objects;

public class Book {
		int id;
	    String name;
	    String author;
	    String publisher;
	    int quantity;
		public Book(int id, String name, String author, String publisher, int quantity) {
			super();
			this.id = id;
			this.name = name;
			this.author = author;
			this.publisher = publisher;
			this.quantity = quantity;
		}
		@Override
		public String toString() {
			return "Book [id=" + id + ", name=" + name + ", author=" + author + ", publisher=" + publisher
					+ ", quantity=" + quantity + "]";
		}
		@Override
		public int hashCode() {
			int prime = 31 ;
			int result = 0 ;
			result = result * prime + id ;
			return result ;
		}
		
		@Override
		public boolean equals(Object obj) {
			if (this == obj)
				return true;
			if (obj == null)
				return false;
			if (getClass() != obj.getClass())
				return false;
			Book obj1 =(Book) obj ;
			if(this.id != obj1.id) {
				return false ;
			}
			if(this.author != obj1.author) {
				return false ;
			}
			return true ;
		}
		
	    
}

Driver Class

import java.util.*;
public class Driver {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		List<Book> library = new ArrayList<>() ;
		
		
		Book b1 = new Book(121, "Let us C", "Yashwant Kanetkar", "BPB", 8);
		Book b2 = new Book(233, "Operating System", "Galvin", "Wiley", 6);
		Book b3 = new Book(101, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
		Book b4 = new Book(121, "Let us C", "Yashwant Kanetkar", "Mc Graw Hill", 11);
		
		library.add(b1);
		library.add(b2);
		library.add(b3);
		library.add(b4);
		List<Book> notDup = new ArrayList<>();
		boolean isSame = false ; 
		int duplicate = 0 ; 
		int notDuplicate = 0 ;
		int quantity = 0 ;
		for(int i = 0 ; i < library.size()-1 ; i++) {
			isSame = false ;
			for(int k = i+1 ; k < library.size() ; k++) {
				if(library.get(i).equals(library.get(k))) {
					duplicate++ ;
					System.out.println("No. of Duplicate Book :" + duplicate);
					isSame = true ;
					System.out.println(library.get(i));
				}
			}
			if(!isSame) {
				notDuplicate++ ;
				notDup.add(library.get(i));
				if(quantity < library.get(i).quantity) {
					quantity = library.get(i).quantity ;
				}
			}
		}
		
		
		for(Book k : notDup) {
			if(k.quantity == quantity) {
				System.out.println(k);
			}
		}
	}

}

OUTPUT