How to Effectively Answer ‘What Are OOPs Concepts in Java?’ in an Interview

Java Interview Tips

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This article aims to provide a comprehensive guide to the most important Java interview question that is what are OOPs concepts in java?

Why should you read it till the end ?

This guide is not just about the “right” answer to this common Java interview question — it’s about how to answer effectively during the interview.
We’ll focus on strategies for responding to key Java topics in a way that demonstrates your proficiency in the shortest time possible, while leaving a lasting impression on your interviewer.
To make a stronger impression, you need to go beyond the textbook definitions and provide deeper insights that demonstrate both your understanding and your ability to apply OOP concepts effectively.

As a someone who has conducted numerous interviews, I have asked the question “what are OOPs concepts in java many times”. However, I often receive basic and overly simplistic answers, like “Polymorphis is one thing taking many forms”. While these answers are technically correct, they really dont help candidates stand out.

What are oops concepts in java ?

Java is based on four main OOP that means object oriented principals, let me go through them one by one.

Encapsulation

Encapsulation means keeping data and methods in one place and controlling access to them using access modifiers (like private and public). Encapsulation helps protect data. Example of encapsulation would be Java class.

Inheritance

This allows one class to inherit properties and methods from another, Inheritance promotes code reuse by enabling you to create new classes based on existing ones, making it easier to maintain and extend your code.

Polymorphism:

This concept enables methods to behave differently depending on the object calling them. Polymorphism can be achieved through

Method overloading(Compile time polymorphism) — Which is achieved using same method name, different parameters.

Method Overriding(Run time polymorphism) — Changing method behavior in a subclass inherited from super class.

Abstraction:

Abstraction allows you to focus on what an object does rather than how it does it. It helps in reducing complexity by providing a simplified view of the system.

In Java, abstraction is typically achieved using abstract classes and interfaces. An abstract class can have both abstract methods (methods without a body) and concrete methods (methods with a body), while an interface only contains abstract methods (before Java 8) and constants.

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