36 OOP · Principles questions from the Computer Science Fundamentals bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
Sign up free to see every answer with its explanation and ask the AI tutor.
A.the ability of one interface or name to take many forms depending on the object or arguments
B.a field whose own copy belongs to each object created from a class
C.the guideline 'do not repeat yourself', avoiding duplicated logic by factoring it into one place
D.a paradigm organizing software around objects that bundle data and the behavior acting on it
Answer + AI explanation with a free account
2. Which term means: "a paradigm organizing software around objects that bundle data and the behavior acting on it"?
Junior
A.instance variable
B.inheritance
C.object-oriented programming
D.message passing
Answer + AI explanation with a free account
3. Which statement is correct?
Junior
A.object-oriented programming — the ability of one interface or name to take many forms depending on the object or arguments
B.object-oriented programming — bundling data and methods in one unit and restricting direct external access to the internal state
C.object-oriented programming — a class is the abstract template, while an object is a concrete instance occupying memory at runtime
D.object-oriented programming — a paradigm organizing software around objects that bundle data and the behavior acting on it
Answer + AI explanation with a free account
4. What is class?
Junior
A.the ability of one interface or name to take many forms depending on the object or arguments
B.a paradigm organizing software around objects that bundle data and the behavior acting on it
C.a blueprint defining the attributes and methods that its objects will have
D.a class is the abstract template, while an object is a concrete instance occupying memory at runtime
Answer + AI explanation with a free account
5. Which term means: "a blueprint defining the attributes and methods that its objects will have"?
Junior
A.polymorphism
B.message passing
C.object-oriented programming
D.class
Answer + AI explanation with a free account
6. Which statement is correct?
Junior
A.class — the ability of one interface or name to take many forms depending on the object or arguments
B.class — a blueprint defining the attributes and methods that its objects will have
C.class — abstraction hides complexity at the design level, while encapsulation hides data by bundling and access control
D.class — bundling data and methods in one unit and restricting direct external access to the internal state
Answer + AI explanation with a free account
7. What is object?
Junior
A.a blueprint defining the attributes and methods that its objects will have
B.exposing only essential features of an entity while hiding its complex implementation details
C.a concrete instance of a class holding its own state in memory
D.bundling data and methods in one unit and restricting direct external access to the internal state
Answer + AI explanation with a free account
8. Which term means: "a concrete instance of a class holding its own state in memory"?
Junior
A.abstraction
B.DRY principle
C.object
D.abstraction vs encapsulation
Answer + AI explanation with a free account
9. Which statement is correct?
Junior
A.object — a field whose own copy belongs to each object created from a class
B.object — a paradigm organizing software around objects that bundle data and the behavior acting on it
C.object — a class is the abstract template, while an object is a concrete instance occupying memory at runtime
D.object — a concrete instance of a class holding its own state in memory
Answer + AI explanation with a free account
10. What is encapsulation?
Junior
A.bundling data and methods in one unit and restricting direct external access to the internal state
B.objects interacting by invoking each other's methods rather than accessing fields directly
C.a paradigm organizing software around objects that bundle data and the behavior acting on it
D.a mechanism where a derived class acquires the attributes and behavior of a base class
Answer + AI explanation with a free account
11. Which term means: "bundling data and methods in one unit and restricting direct external access to the internal state"?
Junior
A.encapsulation
B.inheritance
C.DRY principle
D.message passing
Answer + AI explanation with a free account
12. Which statement is correct?
Junior
A.encapsulation — exposing only essential features of an entity while hiding its complex implementation details
B.encapsulation — the guideline 'do not repeat yourself', avoiding duplicated logic by factoring it into one place
C.encapsulation — a concrete instance of a class holding its own state in memory
D.encapsulation — bundling data and methods in one unit and restricting direct external access to the internal state
Answer + AI explanation with a free account
13. What is abstraction?
Junior
A.exposing only essential features of an entity while hiding its complex implementation details
B.a paradigm organizing software around objects that bundle data and the behavior acting on it
C.the ability of one interface or name to take many forms depending on the object or arguments
D.bundling data and methods in one unit and restricting direct external access to the internal state
Answer + AI explanation with a free account
14. Which term means: "exposing only essential features of an entity while hiding its complex implementation details"?
Junior
A.polymorphism
B.class vs object
C.abstraction
D.instance variable
Answer + AI explanation with a free account
15. Which statement is correct?
Junior
A.abstraction — exposing only essential features of an entity while hiding its complex implementation details
B.abstraction — a concrete instance of a class holding its own state in memory
C.abstraction — a mechanism where a derived class acquires the attributes and behavior of a base class
D.abstraction — bundling data and methods in one unit and restricting direct external access to the internal state
Answer + AI explanation with a free account
16. What is inheritance?
Junior
A.a mechanism where a derived class acquires the attributes and behavior of a base class
B.a blueprint defining the attributes and methods that its objects will have
C.a concrete instance of a class holding its own state in memory
D.the guideline 'do not repeat yourself', avoiding duplicated logic by factoring it into one place
Answer + AI explanation with a free account
17. Which term means: "a mechanism where a derived class acquires the attributes and behavior of a base class"?
Junior
A.instance variable
B.message passing
C.DRY principle
D.inheritance
Answer + AI explanation with a free account
18. Which statement is correct?
Junior
A.inheritance — exposing only essential features of an entity while hiding its complex implementation details
B.inheritance — a mechanism where a derived class acquires the attributes and behavior of a base class
C.inheritance — bundling data and methods in one unit and restricting direct external access to the internal state
D.inheritance — a concrete instance of a class holding its own state in memory
Answer + AI explanation with a free account
19. What is polymorphism?
Junior
A.the guideline 'do not repeat yourself', avoiding duplicated logic by factoring it into one place
B.the ability of one interface or name to take many forms depending on the object or arguments
C.abstraction hides complexity at the design level, while encapsulation hides data by bundling and access control
D.a field whose own copy belongs to each object created from a class
Answer + AI explanation with a free account
20. Which term means: "the ability of one interface or name to take many forms depending on the object or arguments"?
Junior
A.instance variable
B.DRY principle
C.abstraction
D.polymorphism
Answer + AI explanation with a free account
21. Which statement is correct?
Junior
A.polymorphism — bundling data and methods in one unit and restricting direct external access to the internal state
B.polymorphism — the ability of one interface or name to take many forms depending on the object or arguments
C.polymorphism — a blueprint defining the attributes and methods that its objects will have
D.polymorphism — a field whose own copy belongs to each object created from a class
Answer + AI explanation with a free account
22. What is abstraction vs encapsulation?
Mid
A.a paradigm organizing software around objects that bundle data and the behavior acting on it
B.a class is the abstract template, while an object is a concrete instance occupying memory at runtime
C.objects interacting by invoking each other's methods rather than accessing fields directly
D.abstraction hides complexity at the design level, while encapsulation hides data by bundling and access control
Answer + AI explanation with a free account
23. Which term means: "abstraction hides complexity at the design level, while encapsulation hides data by bundling and access control"?
Mid
A.object
B.abstraction vs encapsulation
C.class vs object
D.class
Answer + AI explanation with a free account
24. Which statement is correct?
Mid
A.abstraction vs encapsulation — abstraction hides complexity at the design level, while encapsulation hides data by bundling and access control
B.abstraction vs encapsulation — objects interacting by invoking each other's methods rather than accessing fields directly
C.abstraction vs encapsulation — a mechanism where a derived class acquires the attributes and behavior of a base class
D.abstraction vs encapsulation — the ability of one interface or name to take many forms depending on the object or arguments
Answer + AI explanation with a free account
25. What is class vs object?
Mid
A.the ability of one interface or name to take many forms depending on the object or arguments
B.a class is the abstract template, while an object is a concrete instance occupying memory at runtime
C.a paradigm organizing software around objects that bundle data and the behavior acting on it
D.a mechanism where a derived class acquires the attributes and behavior of a base class
Answer + AI explanation with a free account
26. Which term means: "a class is the abstract template, while an object is a concrete instance occupying memory at runtime"?
Mid
A.abstraction
B.class vs object
C.object-oriented programming
D.inheritance
Answer + AI explanation with a free account
27. Which statement is correct?
Mid
A.class vs object — a field whose own copy belongs to each object created from a class
B.class vs object — the guideline 'do not repeat yourself', avoiding duplicated logic by factoring it into one place
C.class vs object — the ability of one interface or name to take many forms depending on the object or arguments
D.class vs object — a class is the abstract template, while an object is a concrete instance occupying memory at runtime
Answer + AI explanation with a free account
28. What is message passing?
Mid
A.a blueprint defining the attributes and methods that its objects will have
B.the guideline 'do not repeat yourself', avoiding duplicated logic by factoring it into one place
C.a mechanism where a derived class acquires the attributes and behavior of a base class
D.objects interacting by invoking each other's methods rather than accessing fields directly
Answer + AI explanation with a free account
29. Which term means: "objects interacting by invoking each other's methods rather than accessing fields directly"?
Mid
A.class vs object
B.class
C.message passing
D.object
Answer + AI explanation with a free account
30. Which statement is correct?
Mid
A.message passing — the ability of one interface or name to take many forms depending on the object or arguments
B.message passing — a paradigm organizing software around objects that bundle data and the behavior acting on it
C.message passing — objects interacting by invoking each other's methods rather than accessing fields directly
D.message passing — exposing only essential features of an entity while hiding its complex implementation details
Answer + AI explanation with a free account
Showing 30 of 36 OOP · Principles questions — the full set, with answers, explanations and an AI tutor on every question, is inside.
Free to start
Answers, AI explanations, and a free readiness check
Sign up free to check your answers with explanations, ask the AI tutor anything on any question, and take the free 2-minute readiness check for a scored result. One full AI mock interview, scored like a real panel, is free when you sign up.