OOPS

Here are some problem statements covering Object-Oriented Programming (OOP) concepts in Java from basic to advanced:

1. Class and Object Creation: Create a class named Car with attributes like make, model, and year, and then create an object of this class.

2. Encapsulation: Define a class Employee with private attributes like name, age, and salary, and provide public methods to access and modify these attributes.

3. Inheritance: Create a class Vehicle with attributes like make and model, and then create a subclass Car that inherits from Vehicle.

4. Method Overriding: Define a method drive() in both Vehicle and Car classes, and override it in the Car class to provide a different implementation.

5. Polymorphism: Create an array of type Vehicle and store objects of both Vehicle and Car classes in it, then call the drive() method on each object.

6. Abstraction: Create an abstract class Shape with an abstract method calculateArea(), and then create concrete subclasses like Circle and Rectangle that implement this method.

7. Interface Implementation: Define an interface Drawable with a method draw(), and then implement this interface in classes like Circle and Rectangle.

8. Composition: Create a class Engine with attributes like horsepower and fuelType, and then include an instance of this class as an attribute in the Car class.

9. Aggregation: Create a class Department with attributes like name and location, and then include a list of Employee objects as an attribute in the Department class.

10. Association: Create classes Student and Teacher, and establish a bi-directional association between them (i.e., a student can have multiple teachers, and a teacher can have multiple students).

11. Dependency: Define a class Logger with a method log() that takes a message as parameter, and then use this class in other classes like Car and Employee to log messages.

12. Package Creation: Create packages like com.company.model, com.company.service, and com.company.ui, and then define appropriate classes in each package.

13. Access Modifiers: Define attributes with different access modifiers (private, protected, default, public) in a class, and demonstrate their visibility from other classes.

14. Static Keyword: Create a static method calculateArea() in a class MathUtil that calculates the area of a circle, and then call this method without creating an object of MathUtil.

15. Final Keyword: Declare a final variable PI with a value of 3.14 in a class, and demonstrate that its value cannot be changed.

16. Abstract Classes: Define an abstract class Animal with an abstract method makeSound(), and then create concrete subclasses like Dog and Cat that implement this method.

17. Interfaces: Create an interface Playable with a method play(), and then implement this interface in classes like Guitar and Piano.

18. Marker Interfaces: Create a marker interface Serializable with no methods, and then implement it in classes like Book and Customer to indicate that they can be serialized.

19. Nested Classes: Define a nested class Inner within a class Outer, and demonstrate how to access members of the outer class from the inner class.

20. Anonymous Classes: Create an anonymous class that implements an interface or extends a class, and instantiate it inline without giving it a name.

21. Local Classes: Define a local class within a method of another class, and demonstrate how to instantiate it and call its methods.

22. Method References: Define methods like printMessage() and calculateArea() in a class, and then create method references to these methods and pass them as arguments to other methods.

23. Default Methods: Define an interface Resizable with a default method resize(), and then implement this interface in classes like Circle and Rectangle.

24. Static Methods in Interfaces: Define an interface MathOperations with static methods like add() and subtract(), and then call these methods without implementing the interface.

25. Object Cloning: Implement the Cloneable interface in a class like Person, and then demonstrate how to create a shallow copy of an object using the clone() method.

26. Object Serialization: Implement the Serializable interface in a class like Book, and then demonstrate how to serialize and deserialize objects using ObjectOutputStream and ObjectInputStream.

27. Method Overloading: Create multiple versions of a method like calculateArea() in a class Shape that accept different types or numbers of parameters.

28. Method Overriding: Override methods like toString() and equals() in a class like Employee to provide custom implementations.

29. Constructor Overloading: Define multiple constructors in a class like Person that accept different numbers or types of parameters.

These problem statements cover a wide range of OOP concepts in Java, from basic class and object creation to more advanced topics like nested classes, lambda expressions, and object serialization.