Title

import java.util.Random;

public class Book {

    public String title; 
    public static int bookCount;
    private final Date createDate;

    public Book(String title){
        this.title = title;
        this.createDate = new Date();
    }

    public int generateID(){
        Random rand = new Random();
        int Id = rand.nextInt(100);
        bookCount++;
        return Id;
    }

    public int getBookCount(){
        return bookCount;
    }

    // Overwrites default toString()
    public String toString(){
        return("Title of book: " + title);
    }

    public Long shelfLife(){
        Date currentDate = new Date();
        long difference = Math.abs(this.createDate.getTime() - currentDate.getTime());
        return(difference);
    }

    public static void tester(){
        Book book1 = new Book("All about turtles");
        Book book2 = new Book("All about birds");
        System.out.println("ID for book1: " + book1.generateID() + ", " + book1.toString());
        System.out.println("ID for book2: " + book2.generateID() + ", " + book2.toString());
        System.out.println(bookCount);

    }

    public static void main(String[] args){

        tester();
    }
}

Book.main(null);

ID for book1: 64, Title of book: All about turtles
ID for book2: 28, Title of book: All about birds
2

public class Novel extends Book {
    public String author;

    public Novel(String title){
        super(title);
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String newAuthor) {
        this.author = newAuthor;
    }0


    public static void main(String[] args){
        try{
            Novel novel1 = new Novel("Angels and Demons");
            Novel novel2 = new Novel("Harry Potter");
            novel1.setAuthor("Hetvi");
            novel2.setAuthor("J.K. Rowling");

            Thread.sleep(1000);

            System.out.println(novel1.getAuthor());
            System.out.println(novel2.getAuthor());
            System.out.println(novel1.shelfLife());
            System.out.println(novel2.shelfLife());
        }

        catch (Exception e){
            System.out.println(e);
        }
    }
}
Novel.main(null);

Hetvi
J.K. Rowling
1002
1003

public class Textbook extends Book {
    public String author;

    public Textbook(String title){
        super(title);
    }

    public String getAuthor() {
        return author;
    }

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


    public static void main(String[] args){
        try{
            Textbook textbook1 = new Textbook("Turtles are the Best In the World");
            Textbook textbook2 = new Textbook("How to Write Harry Potter");
            textbook1.setAuthor("Nathan Shih");
            textbook2.setAuthor("J.K. Rowling");

            Thread.sleep(1000);

            System.out.println(textbook1.getAuthor());
            System.out.println(textbook2.getAuthor());
            System.out.println(textbook1.shelfLife());
            System.out.println(textbook2.shelfLife());
        }

        catch (Exception e){
            System.out.println(e);
        }
    }
}
Textbook.main(null);

Nathan Shih
J.K. Rowling
1002
1002

class Vehicle {

    public String name; 

    public Vehicle(String name){
        this.name = name;
    }

    public void honk(){
        System.out.println("HONK MEEP BEEEEEEEP!");
    }
}

class Car extends Vehicle {
    public Car(String name){
        super(name);
    }
    // methods and attributes

}

public class Main {
    public static void main(String[] args) {
        Car car1 = new Car("Lexus GS430");

        car1.honk();
        System.out.println(car1.name);
    }
}

// Parent class
public class Animal {
    protected String name;
    protected int age;

    public Animal(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void speak() {
        System.out.println("I AM AN ANIMALIO!!!!!!!!");
    }
}

// Subclass 1
public class Turtle extends Animal {
    private String breed;

    public Turtle(String name, int age, String breed) {
        super(name, age);
        this.breed = breed;
    }

    @Override
    public void speak() {
        System.out.println("Turtle Noises Commence");
    }

    public void eat() {
        System.out.println("I nomp lettuce.");
    }
}

// Subclass 2
public class Cat extends Animal {
    private boolean isIndoor;

    public Cat(String name, int age, boolean isIndoor) {
        super(name, age);
        this.isIndoor = isIndoor;
    }

    @Override
    public void speak() {
        System.out.println("Meow!");
    }

    public void scratch() {
        System.out.println("I am scratching the furniture.");
    }
}

// Tester method
public class AnimalTester {
    public static void main(String[] args) {
        Animal animal1 = new Turtle("Shellby", 3, "Russian Tortoise");
        Animal animal2 = new Cat("Whiskers", 2, true);

        animal1.speak();
        ((Turtle) animal1).eat();
        System.out.println(animal1.name);

        animal2.speak();
        ((Cat) animal2).scratch();
        System.out.println(animal2.age);
    }
}
AnimalTester.main(null);

Turtle Noises Commence
I nomp lettuce.
Shellby
Meow!
I am scratching the furniture.
2