Java OOPs MCQs (Multiple Choice Questions)

Java oops MCQs: Discover the world of Object-Oriented Programming (OOP) in Java through a collection of meticulously crafted Multiple Choice Questions (MCQs). This article offers a comprehensive yet accessible exploration of Object-Oriented Programming (OOP) concepts, from classes and objects to inheritance and polymorphism.

Each question serves as a stepping stone to understanding Java’s OOP paradigm, providing learners with an interactive and engaging method to solidify their knowledge. Whether you’re a beginner seeking a strong foundation or an experienced developer brushing up on OOP principles, these Oops MCQs offer an effective way to enhance your proficiency and confidence in Java’s object-oriented realm.

1.) What is the primary goal of Object-Oriented Programming (OOP)?

A) Improving code readability
B) Maximizing memory usage
C) Enhancing network connectivity
D) Promoting code duplication

Answer: Option A

Explanation: The primary goal of OOP is to improve code organization and readability by modeling real-world entities as objects with attributes (data) and behaviors (methods).

2.) What is an object in Java?

A) A blueprint for creating classes
B) A template for creating methods
C) An instance of a class with its own state and behavior
D) A reserved keyword in Java

Answer: Option C

Explanation: An object is a concrete instance of a class, encapsulating both data (attributes) and methods (behaviors) that operate on the data.

3.) Which concept allows you to define multiple methods in OOP with the same name but different parameters in the same class?

A) Polymorphism
B) Inheritance
C) Abstraction
D) Overloading

Answer: Option D

Explanation: Method overloading enables you to define multiple methods in the same class with the same name but different parameter lists, providing flexibility and clarity.

4.) What is the purpose of the “super” keyword in Java?

A) To create a new instance of a class
B) To access static methods
C) To call the constructor of the superclass
D) To initialize instance variables

Answer: Option C

Explanation: The “super” keyword is used to invoke the constructor of the superclass in a subclass constructor.

5.) Which OOP concept allows you to define a new class based on an existing class, inheriting its attributes and methods?

A) Abstraction
B) Polymorphism
C) Encapsulation
D) Inheritance

Answer: Option D

Explanation: Inheritance is the mechanism that allows a new class (subclass or derived class) to inherit properties and behaviors from an existing class (superclass or base class).

6.) What is encapsulation in Java?

A) Hiding the internal details of an object and providing a public interface
B) Defining multiple methods with the same name but different parameters
C) Creating a new class from an existing class
D) Storing data in a single variable

Answer: Option A

Explanation: Encapsulation refers to the practice of bundling data (attributes) and methods (behaviors) that operate on the data into a single unit (class), while hiding the implementation details from the outside.

7.) Which access modifier allows a class’s members (fields and methods) to be accessible only within the same package?

A) private
B) protected
C) public
D) default (package-private)

Answer: Option D

Explanation: The default access modifier (no modifier) allows class members to be accessible within the same package but not outside it.

8.) What is the relationship between a superclass and a subclass in Java?

A) Unrelated classes
B) Independent classes
C) Parent-child classes
D) Identical classes

Answer: Option C

Explanation: A subclass is derived from a superclass, inheriting its attributes and methods, and adding or modifying behavior as needed.

9.) Which OOP concept allows a class to implement multiple interfaces?

A) Inheritance
B) Polymorphism
C) Encapsulation
D) Interface implementation

Answer: Option A

Explanation: Inheritance allows a class to inherit from a superclass and implement multiple interfaces, enabling it to acquire both behaviors.

10.) What is the purpose of the “this” keyword in Java?

A) To create a new instance of a class
B) To refer to the current instance of the class
C) To access static members of the class
D) To define constructors

Answer: Option B

Explanation: The “this” keyword refers to the current instance of the class and is often used to disambiguate between instance variables and parameters with the same name.

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