Answers in 2024

Object-Oriented Programming is one of the fundamental principles within the programming world, consequently, every interview which you attend calls for expertise of OOPs. This article compiles the maximum often asked OOPs Interview Questions for freshers so one can assist you ace your interviews. So move in advance and get organized.

Let’s take a brief examine all the topics of debate:

Basic OOPs Interview Questions
OOPs Interview Questions Classes and Objects
Interview Questions on Features of OOPs

Inheritance
Polymorphism
Encapsulation
Data abstraction

Methods and capabilities Interview Questions
Exception dealing with Interview Questions
Limitations of OOPs

OOPs Interview Questions

What is the distinction between OOP and SOP?
What is OOPs?
Why use OOPs?
What are the main capabilities of OOPs?
What is an object?
What is a category?
What is the difference between a category and a structure?
Can you name the bottom elegance method with out growing an instance?
What is the difference among a class and an object?
What is inheritance?

Basic OOPs Interview Questions for Freshers

1. What is the difference among OOP and SOP?

2. What is Object Oriented Programming?

Object-Oriented Programming(OOPs) is a type of programming this is based on gadgets in preference to just features and strategies. Individual objects are grouped into classes. OOPs implements actual-global entities like inheritance, polymorphism, hiding, and so forth into programming. It also lets in binding statistics and code collectively.

3. Why use OOPs?

OOPs allows clarity in programming thereby allowing simplicity in fixing complex issues
Code may be reused via inheritance thereby reducing redundancy
Data and code are bound together by means of encapsulation
OOPs lets in statistics hiding, consequently, private information is kept exclusive
Problems may be divided into special parts making it easy to clear up
The idea of polymorphism offers flexibility to this system by using permitting the entities to have more than one forms

4. What are the main functions of OOPs?

Inheritance
Encapsulation
Polymorphism
Data Abstraction

Classes and Objects OOPs Interview Questions and Answers

5. What is an item?

An object is a actual-world entity that is the fundamental unit of OOPs for example chair, cat, dog, and so forth. Different items have distinct states or attributes, and behaviors.

6. What is a category?

A elegance is a prototype that includes gadgets in one of a kind states and with unique behaviors. It has a number of strategies which are common the items gift within that elegance.

7. What is the distinction between a category and a shape?

Class: User-defined blueprint from which gadgets are created. It includes techniques or set of instructions which might be to be finished on the items.

Structure: A shape is essentially a user-defined collection of variables which can be of different facts kinds.

8. Can you call the bottom class method without growing an example?

Yes, you could call the base class without instantiating it if:

It is a static approach
The base magnificence is inherited by using some other subclass

9. What is the distinction between a category and an object?

OOPs Interview Questions – Inheritance

10. What is inheritance?

Inheritance is a characteristic of OOPs which allows classes inherit commonplace homes from other lessons. For example, if there's a class which includes ‘automobile’, different lessons like ‘automobile’, ‘motorcycle’, and many others can inherit commonplace houses from the vehicle class. This property allows you put off redundant code thereby reducing the overall length of the code.

11. What are the special varieties of inheritance?

Single inheritance
Multiple inheritance
Multilevel inheritance
Hierarchical inheritance
Hybrid inheritance

12. What is the difference among a couple of and multilevel inheritance?

13. What is hybrid inheritance?

Hybrid inheritance is a mixture of more than one and multi-stage inheritance.

14. What is hierarchical inheritance?

Hierarchical inheritance refers to inheritance where one base magnificence has a couple of subclasses. For instance, the car class can have ‘automobile’, ‘motorbike’, and many others as its subclasses.

15. What are the restrictions of inheritance?

Increases the effort and time required to execute a application because it calls for leaping from side to side between exceptional lessons
The parent elegance and the child elegance get tightly coupled
Any changes to this system could require adjustments both within the figure as well as the child elegance
Needs careful implementation else could cause wrong effects

16. What is a superclass?

A superclass or base magnificence is a category that acts as a discern to some other magnificence or training. For instance, the Vehicle magnificence is a superclass of class Car.

17. What is a subclass?

A magnificence that inherits from another elegance is known as the subclass. For example, the class Car is a subclass or a derived of Vehicle elegance.

OOPs Interview Questions – Polymorphism

18. What is polymorphism?

Polymorphism refers to the capacity to exist in multiple bureaucracy. Multiple definitions may be given to a single interface. For example, if you have a class named Vehicle, it could have a way named pace however you cannot outline it due to the fact extraordinary cars have distinctive pace. This method may be defined inside the subclasses with extraordinary definitions for one-of-a-kind vehicles.

19. What is static polymorphism?

Static polymorphism (static binding) is a sort of polymorphism that occurs at assemble time. An instance of assemble-time polymorphism is approach overloading.

20. What is dynamic polymorphism?

Runtime polymorphism or dynamic polymorphism (dynamic binding) is a type of polymorphism which is resolved at some point of runtime. An instance of runtime polymorphism is method overriding.

21. What is method overloading?

Method overloading is a characteristic of OOPs which makes it feasible to present the same call to more than one strategies inside a category if the arguments exceeded range.

22. What is approach overriding?

Method overriding is a function of OOPs by way of which the child magnificence or the subclass can redefine techniques gift inside the base magnificence or parent magnificence. Here, the approach this is overridden has the equal name as well as the signature which means the arguments exceeded and the go back type.

23. What is operator overloading?

Operator overloading refers to imposing operators the use of consumer-described types based totally at the arguments exceeded at the side of it.

24. Differentiate among overloading and overriding.

OOPs Interview Questions – Encapsulation

25. What is encapsulation?

Encapsulation refers to binding the records and the code that works on that collectively in a single unit. For example, a class. Encapsulation also permits facts-hiding as the records specified in one elegance is hidden from other lessons.

26. What are ‘get right of entry to specifiers’?

Access specifiers or get right of entry to modifiers are key phrases that determine the accessibility of techniques, classes, and so on in OOPs. These get right of entry to specifiers allow the implementation of encapsulation. The maximum not unusual get admission to specifiers are public, private and protected. However, there are a few more which are unique to the programming languages.

27. What is the difference between public, non-public and guarded get entry to modifiers?

Data abstraction

28. What is records abstraction?

Data abstraction is a completely crucial function of OOPs that lets in displaying simplest the essential facts and hiding the implementation details. For example, even as using a bike, you understand that if you increase the accelerator, the velocity will growth, but you don’t understand the way it without a doubt takes place. This is records abstraction because the implementation info are hidden from the rider.

29. How to attain records abstraction?

Data abstraction may be executed thru:

Abstract elegance
Abstract method

30. What is an abstract magnificence?

An summary elegance is a category that includes abstract techniques. These strategies are essentially declared but now not described. If these techniques are to be used in some subclass, they want to be solely described inside the subclass.

31. Can you create an example of an summary class?

No. Instances of an abstract magnificence can not be created as it does now not have a complete implementation. However, instances of subclass inheriting the abstract class can be created.

32. What is an interface?

It is a concept of OOPs that permits you to claim techniques with out defining them. Interfaces, in contrast to instructions, aren't blueprints due to the fact they do no longer comprise detailed commands or actions to be completed. Any class that implements an interface defines the methods of the interface.

33. Differentiate among records abstraction and encapsulation.

34. What are virtual features?

Virtual features are capabilities which might be gift inside the determine magnificence and are overridden by means of the subclass. These functions are used to reap runtime polymorphism.

35. What are pure virtual capabilities?

Pure virtual features or summary capabilities are functions which might be simplest declared within the base class. This means that they do now not incorporate any definition in the base class and need to be redefined inside the subclass.

36. What is a constructor?

A constructor is a unique form of method that has the identical name as the class and is used to initialize items of that elegance.

37. What is a destructor?

A destructor is a technique this is mechanically invoked whilst an object is destroyed. The destructor additionally recovers the heap space that turned into allotted to the destroyed item, closes the documents and database connections of the object, and so forth.

38. Types of constructors

Types of constructors vary from language to language. However, all the feasible constructors are:

Default constructor
Parameterized constructor
Copy constructor
Static constructor
Private constructor

39. What is a replica constructor?

A reproduction constructor creates items via copying variables from some other object of the identical elegance. The foremost intention of a duplicate constructor is to create a brand new object from an current one.

40. What is using ‘finalize’?

Finalize as an item approach used to unfastened up unmanaged sources and cleanup earlier than Garbage Collection(GC). It performs memory control tasks.

41. What is Garbage Collection(GC)?

GC is an implementation of automatic reminiscence management. The Garbage collector frees up area occupied by way of gadgets which might be now not in life.

42. Differentiate among a category and a method.

43. Differentiate among an abstract class and an interface?

44. What is a very last variable?

A variable whose cost does not trade. It always refers to the equal item through the belongings of non-transversity.

OOPs Interview Questions – Exception Handling

45. What is an exception?

An exception is a type of notification that interrupts the normal execution of a program. Exceptions provide a pattern to the mistake and switch the error to the exception handler to remedy it. The kingdom of this system is stored as quickly as an exception is raised.

46. What is exception dealing with?

Exception managing in Object-Oriented Programming is a totally important concept this is used to control mistakes. An exception handler allows errors to be thrown and caught and implements a centralized mechanism to remedy them.

47. What is the difference between an error and an exception?

48. What is a attempt/ seize block?

A strive/ seize block is used to deal with exceptions. The try block defines a hard and fast of statements that may result in an blunders. The trap block basically catches the exception.

49. What is a ultimately block?

A subsequently block includes code this is used to execute crucial code consisting of closing a connection, and so forth. This block executes when the strive block exits. It additionally makes certain that ultimately block executes even in case some sudden exception is encountered.

OOPs Interview Questions – Limitations of OOPs

50. What are the restrictions of OOPs?

Usually not appropriate for small issues
Requires intensive trying out
Takes more time to clear up the hassle
Requires proper making plans
The programmer need to think about fixing a trouble in terms of objects

Hope you're clear with all that has been shared with you on this tutorial. This brings us to the cease of our article on OOPs Interview Questions. Make certain you exercise as a lot as viable and revert your revel in.

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Top 50 OOPs Interview Questions and Answers in 2024

Top 50 OOPs Interview Questions and