Top 10 OOPs interview questions and answers.

1.What do you mean by OOPs ?

OOPs stands for object oriented programming system.

It is paradigm which provides the different features such as abstraction,encapsulation,inheritance,polymorphism etc.

2.What are the basic concept of OOPs ?





3.What do you mean by Object.

Object is a real entity which contains state , behaviour and identity.

Example: pen,chair and table etc.

4.What do you mean  by Class

Class is  the blueprint which is used to expose the behaviour of an object.

5.What are the advantages of OOPs ?

It is easy to understand and reduce the complexity.

It is based on the modular technique means break the  large program into small program and solve individually and last integrate all the module into the single unit.

 It is reusable means same code can  be used at the multiple in the project.

6.What do you mean by Abstraction ?

Hiding the internal  details and only showing the functionality is known as abstraction.


Suppose,when we chat with friends on facebook then we simply chatting but we don’t know how it internally works.

7.What is the difference between the object oriented and object based programming language ?

The main difference between the object-oriented programming language and object-based programming language is that object-oriented programming supports all the features of OOPs and object-based programming language also supports all the features of OOPs except inheritance.

8.What do  you mean by Inheritance ?

When  one class acquire all the properties(structure,behaviour,methods etct) of another class then it is known as inheritance.

Example: Parent and child relation

9.What do you mean by Encapsulation ?

Wrapping the data and methods into the single unit is known as encapsulation.

Example:  java class is the combination of data and methods so  java class is an example of encapsulation. 

10. What do you mean by Polymorphism ?

Polymorphism is made of two words poly and morphos.

Poly means many and morphos means forms.

The word polymorphism means having many forms of the one object/things etc


A person at the same time have different characteristics like  father,husband etc.

There are two ways in which we can achieve polymorphism in java by method overloading and method overriding

Thanks and Regards

Placement preparation

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