Java OOP Practice Questions PDF

Java OOP Practice Questions and Solutions 1. Create a class 'Student' with attributes name, age, and grade. Implement methods to display student information and set new values for each attribute. public class Student { private String name; private int age; private char grade;...

Java OOP Practice Questions and Solutions 1. Create a class 'Student' with attributes name, age, and grade. Implement methods to display student information and set new values for each attribute. public class Student { private String name; private int age; private char grade; public Student(String name, int age, char grade) { this.name = name; this.age = age; this.grade = grade; } public void displayInfo() { System.out.println("Name: " + name); System.out.println("Age: " + age); System.out.println("Grade: " + grade); } public void setName(String name) { this.name = name; } public void setAge(int age) { this.age = age; } public void setGrade(char grade) { this.grade = grade; } } 2. Create a class 'Rectangle' with attributes length and width. Include methods to calculate area and perimeter. public class Rectangle { private double length; private double width; public Rectangle(double length, double width) { this.length = length; this.width = width; } public double calculateArea() { return length * width; } public double calculatePerimeter() { return 2 * (length + width); } } 3. Create a class 'BankAccount' with attributes accountNumber, balance, and accountHolderName. Implement methods for deposit, withdrawal, and balance inquiry. public class BankAccount { private String accountNumber; private double balance; private String accountHolderName; public BankAccount(String accountNumber, double initialBalance, String accountHolderName) {  this.accountNumber = accountNumber; this.balance = initialBalance; this.accountHolderName = accountHolderName; } public void deposit(double amount) { if(amount > 0) balance += amount; } public void withdraw(double amount) { if(amount 0 && discount < price) price -= discount;  } } 7. Implement a 'Employee' class with attributes name, ID, and salary. Add methods to raise salary by a given percentage and display information. public class Employee { private String name; private int id; private double salary; public Employee(String name, int id, double salary) { this.name = name; this.id = id; this.salary = salary; } public void raiseSalary(double percentage) { salary += salary * percentage / 100; } public void displayInfo() { System.out.println("Name: " + name + ", ID: " + id + ", Salary: $" + salary); } } 8. Create a 'Library' class with methods to add and remove books, search by title, and list all books. import java.util.ArrayList; public class Library { private ArrayList books = new ArrayList(); public void addBook(Book book) { books.add(book); } public void removeBook(String title) { books.removeIf(book -> book.getTitle().equals(title)); } public Book searchByTitle(String title) { for(Book book : books) { if(book.getTitle().equals(title)) return book; } return null; } public void listAllBooks() { for(Book book : books) { book.displayDetails(); } } } 9. Design a 'Shape' class hierarchy with classes like Circle, Rectangle, and Triangle inheriting from Shape, each with area calculation methods. abstract class Shape { public abstract double area(); } class Circle extends Shape { private double radius; public Circle(double radius) { this.radius = radius; } public double area() { return Math.PI * radius * radius; } } class Rectangle extends Shape { private double length, width; public Rectangle(double length, double width) { this.length = length; this.width = width; } public double area() { return length * width; } } class Triangle extends Shape { private double base, height; public Triangle(double base, double height) { this.base = base; this.height = height; } public double area() { return 0.5 * base * height; } } 10. Implement a 'Person' class with attributes name and age. Create subclasses 'Student' and 'Teacher' with additional attributes and methods specific to each. public class Person {  private String name; private int age; public Person(String name, int age) { this.name = name; this.age = age; } public void display() { System.out.println("Name: " + name + ", Age: " + age); } } class Student extends Person { private String studentID; public Student(String name, int age, String studentID) { super(name, age); this.studentID = studentID; } public void display() { super.display(); System.out.println("Student ID: " + studentID); } } class Teacher extends Person { private String subject; public Teacher(String name, int age, String subject) { super(name, age); this.subject = subject; } public void display() { super.display(); System.out.println("Subject: " + subject); } }