OOPs Interview Questions Answers

In this blog post, we will discuss OOPs Interview Questions Answers based in 2023, here we have provided you top 30 questions and answers related to OOPs programming language, which are asked in interview. If you go for an interview in any IT sector company, then all these questions are may be definitely asked. That’s why we have prepared top 30 questions and answers for you on this blog related OOPs (Object-Oriented Programming).

OOPs Interview Questions Answers

Question 1. What is OOPs?

Answer: Object-Oriented Programming (OOPs) is a programming paradigm based on the concept of “objects,” which can contain data and code to manipulate that data.

 

Question 2. What is an object?

Answer: An object is an instance of a class, which is a blueprint or template that defines the properties and behaviors of the objects of that class.

 

Question 3. What is a class?

Answer: A class is a blueprint or template that defines the properties and behaviors of a set of objects.

Question 4. What are the four pillars of OOPs?

Answer: The four pillars of OOPs are inheritance, encapsulation, abstraction, and polymorphism.

 

Question 5. What is inheritance?

Answer: Inheritance is a mechanism in which a new class is derived from an existing class, and it inherits all the properties and methods of the parent class.

 

Question 6. What is encapsulation?

Answer: Encapsulation is the process of hiding the implementation details of an object from the outside world and exposing only the necessary details through a public interface.

 

Question 7. What is abstraction?

Answer: Abstraction is the process of representing essential features of an object without including unnecessary details.

 

Question 8. What is polymorphism?

Answer: Polymorphism is the ability of objects of different types to be treated as if they are of the same type.




Question 9. What is the difference between abstract class and interface?

Answer: An abstract class can contain both concrete and abstract methods, while an interface can only contain abstract methods.

 

Question 10. What is method overloading?

Answer: Method overloading is a feature that allows a class to have two or more methods with the same name but different parameters.

 

Question 11. What is method overriding?

Answer: Method overriding is a feature that allows a subclass to provide its own implementation of a method that is already defined in its superclass.

 

Question 12. What is a constructor?

Answer: A constructor is a special method that is used to create an object of a class.

 

Question 13. What is a destructor?

Answer: A destructor is a special method that is used to destroy an object of a class.

 

Question 14. What is the difference between private and protected access modifiers?

Answer: Private members can only be accessed within the same class, while protected members can be accessed within the same class and its subclasses.

Question 15. What is a static method?

Answer: A static method is a method that belongs to a class rather than an instance of the class, and can be called without creating an object of the class.

OOPs Interview Questions Answers

Question 16. What is a static variable?

Answer: A static variable is a variable that belongs to a class rather than an instance of the class, and is shared by all instances of the class.




Question 17. What is a final class?

Answer: A final class is a class that cannot be subclassed.

 

Question 18. What is a final method?

Answer: A final method is a method that cannot be overridden in a subclass.

 

Question 19. What is a final variable?

Answer: A final variable is a variable that cannot be changed once it has been assigned a value.

 

Question 20. What is an abstract method?

Answer: An abstract method is a method that does not have an implementation in the class where it is declared, but must be implemented in its subclasses.

 

Question 21. What is a virtual function?

Answer: A virtual function is a function that is declared in a base class and can be overridden in its derived classes.

 

Question 22. What is the difference between a stack and a heap?

Answer: A stack is a region of memory used to store variables created by a function, while a heap is a region of memory used to store dynamically allocated variables.

 

Question 23. What is garbage collection?

Answer: Garbage collection is the process of automatically freeing memory that is no longer being used by a program.

Question 24. What is method hiding in OOPs?

Answer: Method hiding is a mechanism in which a subclass provides a new implementation for a static method that is already defined in its superclass. The method in the superclass is not accessible to the subclass.

 

Question 25. What is the concept of “this” pointer in OOPs?

Answer: In OOPs, “this” is a reference variable that points to the current object of a class. It is used to refer to the instance variables and methods of the class from within the class itself.

 

Question 26. What is the difference between composition and inheritance?

Answer: Composition is a design principle in which a class contains objects of other classes as its members, while inheritance is a mechanism in which a class inherits properties and behaviors from its superclass. Composition allows for greater flexibility and reusability in object relationships compared to inheritance.

 

Question 27. What is a design pattern in OOPs?

Answer: A design pattern is a reusable solution to a common design problem in software development. It provides a proven and efficient way to design and implement software systems using OOPs principles and practices.




Question 28. What is the SOLID principle in OOPs?

Answer: The SOLID principle is a set of five design principles in OOPs that promote maintainable and extensible software. It stands for Single Responsibility Principle, Open/Closed Principle, Lis kov Substitution Principle, Interface Segregation Principle, and Dependency Inversion Principle.

Question 29. What is the difference between method overloading and method overriding?

Answer: Method overloading is the ability to have multiple methods with the same name but different parameters in a class, while method overriding is the ability of a subclass to provide a new implementation for a method that is already defined in its superclass. Method overloading is resolved at compile-time based on the number or type of parameters, while method overriding is resolved at runtime based on the actual object type.

 

Question 30. How does OOPs promote code reusability?

Answer: OOPs promotes code reusability through features like inheritance, composition, and polymorphism. Inheritance allows a class to inherit properties and behaviors from its superclass, making it easy to reuse code. Composition allows objects of one class to be used as members in another class, enabling code reuse by building complex objects from smaller, reusable objects. Polymorphism allows objects of different types to be treated as if they are of the same type, providing a consistent way to interact with objects and reuse code across different objects and classes.

Conclusion

So, you have learned here Top 30, OOPs Interview Questions Answers, all these questions are very important. I hope you have understood all questions and answers very well and if you have any doubt, regarding it then you can ask in the comment section.

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