OOP

Question 1

Class:

Answer 1

Blueprint for creating objects. It defines a data structure that includes data members (fields) and methods.

Question 2

Object:

Answer 2

An instance of a class. It represents a real-world entity and has state and behavior.

Question 3

Inheritance:

Answer 3

Mechanism where a new class inherits properties and behaviors from an existing class. It promotes code reuse.

Question 4

Polymorphism

Answer 4

Ability of a class to take on multiple forms. It allows objects of different classes to be treated as objects of a common base class.

Question 5

Encapsulation

Answer 5

Bundling of data (attributes) and methods that operate on the data within a single unit (class). It restricts direct access to some of an object’s components.

Question 6

Abstraction

Answer 6

Concept of hiding complex implementation details and showing only the necessary features of an object.

Question 7

Constructor

Answer 7

Special method used for initializing objects. It is called when an object is created.

Question 8

Method Overloading

Answer 8

Defining multiple methods in the same class with the same name but different parameters.

Question 9

Interface

Answer 9

A collection of abstract methods. It defines a contract for classes that implement it.

Question 10

Package:

Answer 10

A way to organize related classes into a single directory. It helps in avoiding naming conflicts.

Question 11

Access Modifiers:

Answer 11

Keywords (public, private, protected) that control the visibility of class members (attributes and methods).

Question 12

Final Keyword:

Answer 12

A keyword used to make a class, method, or variable unmodifiable or prevent inheritance.

Question 13

Static Keyword:

Answer 13

A keyword used to define class members that belong to the class rather than instances of the class.

Question 14

This Keyword:

Answer 14

A keyword used to refer to the current instance of the class. It is used to distinguish between instance variables and method parameters.

Question 15

Super Keyword:

Answer 15

A keyword used to refer to the superclass. It is used to call methods or access attributes of the superclass.

Question 16

Method Overriding:

Answer 16

Providing a specific implementation for a method that is already defined in the superclass.

Question 17

Method Overloading:

Answer 17

Defining multiple methods in the same class with the same name but different parameters.

Question 18

Abstract Class:

Answer 18

A class that cannot be instantiated and may contain abstract methods. It is meant to be subclassed.

Question 19

Encapsulation:

Answer 19

Bundling of data (attributes) and methods that operate on the data within a single unit (class). It restricts direct access to some of an object’s components.

Question 20

Composition:

Answer 20

A relationship between classes where one class contains an object of another class. It represents a “whole-part” relationship.

Question 21

Aggregation:

Answer 21

A form of association where one class contains an object of another class. It represents a weaker relationship compared to composition.

Question 22

Abstract Method:

Answer 22

A method without a body (implementation) defined in an abstract class or interface. Subclasses provide the implementation.

Question 23

Final Class:

Answer 23

A class that cannot be subclassed. It is marked as final using the “final” keyword.

Question 24

Final Method:

Answer 24

A method that cannot be overridden by subclasses. It is marked as final using the “final” keyword.

Question 25

Final Variable:

Answer 25

A variable whose value cannot be changed after initialization. It is marked as final using the “final” keyword.

Question 26

Static Method:

Answer 26

A method that belongs to the class rather than instances of the class. It can be called without creating an object.

Question 27

Static Variable:

Answer 27

A variable that belongs to the class rather than instances of the class. It is shared among all instances.

Question 28

Instance Variable:

Answer 28

A variable that belongs to an instance of a class. Each instance has its own copy.

Question 29

Class Variable:

Answer 29

A variable that belongs to the class rather than instances of the class. It is shared among all instances.

Question 30

Abstract Class:

Answer 30

A class that cannot be instantiated and may contain abstract methods. It is meant to be subclassed.

Question 31

Abstract Method:

Answer 31

A method without a body (implementation) defined in an abstract class or interface. Subclasses provide the implementation.

Question 32

Override Annotation:

Answer 32

An annotation used in Java to indicate that a method is intended to override a method in a superclass.

Question 33

Protected Access Modifier:

Answer 33

Access modifier that allows access within the same package and by subclasses, but not outside the package.

Question 34

Public Access Modifier:

Answer 34

Access modifier that allows unrestricted access to the class, its attributes, and methods.

Question 35

Private Access Modifier:

Answer 35

Access modifier that restricts access to the class, its attributes, and methods only within the same class.

Question 36

Default (Package-Private) Access Modifier:

Answer 36

Access modifier that allows access within the same package but not outside the package. It is the default access level.

Question 37

Getter Method:

Answer 37

A method used to retrieve the value of a private attribute. It follows the naming convention “getVariableName.”

Question 38

Setter Method:

Answer 38

A method used to set the value of a private attribute. It follows the naming convention “setVariableName.”

Question 39

Dynamic Binding:

Answer 39

The process of linking a method call to its implementation at runtime. It enables polymorphism.

Question 40

Object-Oriented Programming (OOP):

Answer 40

A programming paradigm based on the concept of objects, which represent real-world entities and have state and behavior.