Java OOP MCQ Questions with Answers (Latest 2026)

Q1. Which option best describes a class?

A. A pure file. B. Blueprint for objects. C. A pure interface. D. A pure module.

Select an answer to check.

Answer: Blueprint for objects.

Here, Blueprint for objects. is the right choice. Defines fields and methods. It aligns directly with what the question asks about which option best describes a class. A quick elimination of partially true options helps confirm it.

Q2. What is the primary purpose of a class?

A. A pure module. B. Blueprint for objects. C. A pure interface. D. A pure file.

Select an answer to check.

Answer: Blueprint for objects.

In this case, Blueprint for objects. is correct. Defines fields and methods. It aligns directly with what the question asks about what is the primary purpose of a class. A quick elimination of partially true options helps confirm it.

Q3. Which statement about a class is most accurate?

A. A pure module. B. A pure file. C. A pure interface. D. Blueprint for objects.

Select an answer to check.

Answer: Blueprint for objects.

The best option here is Blueprint for objects.. Defines fields and methods. It aligns directly with what the question asks about which statement about a class is most accurate. A quick elimination of partially true options helps confirm it.

Q4. How is a class best characterized?

A. A pure interface. B. A pure module. C. Blueprint for objects. D. A pure file.

Select an answer to check.

Answer: Blueprint for objects.

For this question, Blueprint for objects. is correct. Defines fields and methods. It aligns directly with what the question asks about how is a class best characterized. A quick elimination of partially true options helps confirm it.

Q5. Which option best describes an object?

A. A pure file. B. Instance of a class. C. A pure interface. D. A pure class.

Select an answer to check.

Answer: Instance of a class.

Instance of a class. is the correct answer here. Lives on heap. It aligns directly with what the question asks about which option best describes an object. A quick elimination of partially true options helps confirm it.

Q6. What is the primary purpose of an object?

A. A pure interface. B. Instance of a class. C. A pure file. D. A pure class.

Select an answer to check.

Answer: Instance of a class.

Here, Instance of a class. is the right choice. Lives on heap. This matches the core idea being tested around what is the primary purpose of an object. A quick elimination of partially true options helps confirm it.

Q7. Which statement about an object is most accurate?

A. A pure class. B. Instance of a class. C. A pure file. D. A pure interface.

Select an answer to check.

Answer: Instance of a class.

In this case, Instance of a class. is correct. Lives on heap. This matches the core idea being tested around which statement about an object is most accurate. A quick elimination of partially true options helps confirm it.

Q8. How is an object best characterized?

A. A pure interface. B. Instance of a class. C. A pure file. D. A pure class.

Select an answer to check.

Answer: Instance of a class.

The best option here is Instance of a class.. Lives on heap. This matches the core idea being tested around how is an object best characterized. A quick elimination of partially true options helps confirm it.

Q9. Which option best describes encapsulation?

A. Pure polymorphism. B. Pure inheritance. C. Pure abstraction. D. Hide state behind methods/visibility.

Select an answer to check.

Answer: Hide state behind methods/visibility.

For this question, Hide state behind methods/visibility. is correct. Use private + getters/setters. This matches the core idea being tested around which option best describes encapsulation. A quick elimination of partially true options helps confirm it.

Q10. What is the primary purpose of encapsulation?

A. Pure inheritance. B. Pure abstraction. C. Pure polymorphism. D. Hide state behind methods/visibility.

Select an answer to check.

Answer: Hide state behind methods/visibility.

Hide state behind methods/visibility. is the correct answer here. Use private + getters/setters. This matches the core idea being tested around what is the primary purpose of encapsulation. A quick elimination of partially true options helps confirm it.

Q11. Which statement about encapsulation is most accurate?

A. Pure abstraction. B. Pure inheritance. C. Pure polymorphism. D. Hide state behind methods/visibility.

Select an answer to check.

Answer: Hide state behind methods/visibility.

Here, Hide state behind methods/visibility. is the right choice. Use private + getters/setters. That is exactly the concept behind which statement about encapsulation is most accurate in this context. A quick elimination of partially true options helps confirm it.

Q12. How is encapsulation best characterized?

A. Pure polymorphism. B. Hide state behind methods/visibility. C. Pure inheritance. D. Pure abstraction.

Select an answer to check.

Answer: Hide state behind methods/visibility.

In this case, Hide state behind methods/visibility. is correct. Use private + getters/setters. That is exactly the concept behind how is encapsulation best characterized in this context. A quick elimination of partially true options helps confirm it.

Q13. Which option best describes inheritance?

A. Pure interface only. B. Pure composition. C. Pure abstract only. D. Subclass extends superclass.

Select an answer to check.

Answer: Subclass extends superclass.

The best option here is Subclass extends superclass.. Reuses behavior. That is exactly the concept behind which option best describes inheritance in this context. A quick elimination of partially true options helps confirm it.

Q14. What is the primary purpose of inheritance?

A. Subclass extends superclass. B. Pure abstract only. C. Pure interface only. D. Pure composition.

Select an answer to check.

Answer: Subclass extends superclass.

For this question, Subclass extends superclass. is correct. Reuses behavior. That is exactly the concept behind what is the primary purpose of inheritance in this context. A quick elimination of partially true options helps confirm it.

Q15. Which statement about inheritance is most accurate?

A. Pure interface only. B. Pure composition. C. Subclass extends superclass. D. Pure abstract only.

Select an answer to check.

Answer: Subclass extends superclass.

Subclass extends superclass. is the correct answer here. Reuses behavior. That is exactly the concept behind which statement about inheritance is most accurate in this context. A quick elimination of partially true options helps confirm it.

Q16. How is inheritance best characterized?

A. Pure interface only. B. Pure composition. C. Pure abstract only. D. Subclass extends superclass.

Select an answer to check.

Answer: Subclass extends superclass.

Here, Subclass extends superclass. is the right choice. Reuses behavior. It fits the requirement in the prompt about how is inheritance best characterized. A quick elimination of partially true options helps confirm it.

Q17. Which option best describes polymorphism?

A. Pure inheritance only. B. Pure overloading only. C. Static dispatch only. D. Same call dispatched based on runtime type.

Select an answer to check.

Answer: Same call dispatched based on runtime type.

In this case, Same call dispatched based on runtime type. is correct. Override-based dispatch. It fits the requirement in the prompt about which option best describes polymorphism. A quick elimination of partially true options helps confirm it.

Q18. What is the primary purpose of polymorphism?

A. Static dispatch only. B. Same call dispatched based on runtime type. C. Pure overloading only. D. Pure inheritance only.

Select an answer to check.

Answer: Same call dispatched based on runtime type.

The best option here is Same call dispatched based on runtime type.. Override-based dispatch. It fits the requirement in the prompt about what is the primary purpose of polymorphism. A quick elimination of partially true options helps confirm it.

Q19. Which statement about polymorphism is most accurate?

A. Pure inheritance only. B. Pure overloading only. C. Same call dispatched based on runtime type. D. Static dispatch only.

Select an answer to check.

Answer: Same call dispatched based on runtime type.

For this question, Same call dispatched based on runtime type. is correct. Override-based dispatch. It fits the requirement in the prompt about which statement about polymorphism is most accurate. A quick elimination of partially true options helps confirm it.

Q20. How is polymorphism best characterized?

A. Pure inheritance only. B. Static dispatch only. C. Same call dispatched based on runtime type. D. Pure overloading only.

Select an answer to check.

Answer: Same call dispatched based on runtime type.

Same call dispatched based on runtime type. is the correct answer here. Override-based dispatch. It fits the requirement in the prompt about how is polymorphism best characterized. A quick elimination of partially true options helps confirm it.

Q21. Which option best describes abstraction?

A. Expose what; hide how. B. Pure encapsulation. C. Pure inheritance. D. Pure overriding.

Select an answer to check.

Answer: Expose what; hide how.

Here, Expose what; hide how. is the right choice. Interfaces and abstract classes. This is the most accurate statement for which option best describes abstraction. A quick elimination of partially true options helps confirm it.

Q22. What is the primary purpose of abstraction?

A. Pure inheritance. B. Expose what; hide how. C. Pure overriding. D. Pure encapsulation.

Select an answer to check.

Answer: Expose what; hide how.

In this case, Expose what; hide how. is correct. Interfaces and abstract classes. This is the most accurate statement for what is the primary purpose of abstraction. A quick elimination of partially true options helps confirm it.

Q23. Which statement about abstraction is most accurate?

A. Pure encapsulation. B. Pure inheritance. C. Expose what; hide how. D. Pure overriding.

Select an answer to check.

Answer: Expose what; hide how.

The best option here is Expose what; hide how.. Interfaces and abstract classes. This is the most accurate statement for which statement about abstraction is most accurate. A quick elimination of partially true options helps confirm it.

Q24. How is abstraction best characterized?

A. Pure overriding. B. Pure inheritance. C. Expose what; hide how. D. Pure encapsulation.

Select an answer to check.

Answer: Expose what; hide how.

For this question, Expose what; hide how. is correct. Interfaces and abstract classes. This is the most accurate statement for how is abstraction best characterized. A quick elimination of partially true options helps confirm it.

Q25. Which option best describes an interface?

A. An abstract class. B. A regular class. C. Pure abstract type with method signatures. D. A pure record.

Select an answer to check.

Answer: Pure abstract type with method signatures.

Pure abstract type with method signatures. is the correct answer here. Multiple inheritance of type. This is the most accurate statement for which option best describes an interface. A quick elimination of partially true options helps confirm it.

Q26. What is the primary purpose of an interface?

A. Pure abstract type with method signatures. B. An abstract class. C. A regular class. D. A pure record.

Select an answer to check.

Answer: Pure abstract type with method signatures.

Here, Pure abstract type with method signatures. is the right choice. Multiple inheritance of type. It aligns directly with what the question asks about what is the primary purpose of an interface. The other options are either incomplete or contextually incorrect.

Q27. Which statement about an interface is most accurate?

A. Pure abstract type with method signatures. B. A pure record. C. A regular class. D. An abstract class.

Select an answer to check.

Answer: Pure abstract type with method signatures.

In this case, Pure abstract type with method signatures. is correct. Multiple inheritance of type. It aligns directly with what the question asks about which statement about an interface is most accurate. The other options are either incomplete or contextually incorrect.

Q28. How is an interface best characterized?

A. An abstract class. B. A regular class. C. A pure record. D. Pure abstract type with method signatures.

Select an answer to check.

Answer: Pure abstract type with method signatures.

The best option here is Pure abstract type with method signatures.. Multiple inheritance of type. It aligns directly with what the question asks about how is an interface best characterized. The other options are either incomplete or contextually incorrect.

Q29. Which option best describes an abstract class?

A. Class that may have abstract methods. B. An interface. C. A regular class. D. A record only.

Select an answer to check.

Answer: Class that may have abstract methods.

For this question, Class that may have abstract methods. is correct. Cannot be instantiated. It aligns directly with what the question asks about which option best describes an abstract class. The other options are either incomplete or contextually incorrect.

Q30. What is the primary purpose of an abstract class?

A. A record only. B. A regular class. C. An interface. D. Class that may have abstract methods.

Select an answer to check.

Answer: Class that may have abstract methods.

Class that may have abstract methods. is the correct answer here. Cannot be instantiated. It aligns directly with what the question asks about what is the primary purpose of an abstract. The other options are either incomplete or contextually incorrect.

Q31. Which statement about an abstract class is most accurate?

A. An interface. B. A regular class. C. Class that may have abstract methods. D. A record only.

Select an answer to check.

Answer: Class that may have abstract methods.

Here, Class that may have abstract methods. is the right choice. Cannot be instantiated. This matches the core idea being tested around which statement about an abstract class is most. The other options are either incomplete or contextually incorrect.

Q32. How is an abstract class best characterized?

A. A regular class. B. Class that may have abstract methods. C. An interface. D. A record only.

Select an answer to check.

Answer: Class that may have abstract methods.

In this case, Class that may have abstract methods. is correct. Cannot be instantiated. This matches the core idea being tested around how is an abstract class best characterized. The other options are either incomplete or contextually incorrect.

Q33. Which option best describes default methods?

A. Interface methods with implementations (Java 8+). B. Pure static methods only. C. Pure private methods. D. Abstract methods only.

Select an answer to check.

Answer: Interface methods with implementations (Java 8+).

The best option here is Interface methods with implementations (Java 8+).. Backwards-compatible API additions. This matches the core idea being tested around which option best describes default methods. The other options are either incomplete or contextually incorrect.

Q34. What is the primary purpose of default methods?

A. Abstract methods only. B. Pure static methods only. C. Interface methods with implementations (Java 8+). D. Pure private methods.

Select an answer to check.

Answer: Interface methods with implementations (Java 8+).

For this question, Interface methods with implementations (Java 8+). is correct. Backwards-compatible API additions. This matches the core idea being tested around what is the primary purpose of default methods. The other options are either incomplete or contextually incorrect.

Q35. Which statement about default methods is most accurate?

A. Interface methods with implementations (Java 8+). B. Pure private methods. C. Abstract methods only. D. Pure static methods only.

Select an answer to check.

Answer: Interface methods with implementations (Java 8+).

Interface methods with implementations (Java 8+). is the correct answer here. Backwards-compatible API additions. This matches the core idea being tested around which statement about default methods is most accurate. The other options are either incomplete or contextually incorrect.

Q36. How is default methods best characterized?

A. Interface methods with implementations (Java 8+). B. Abstract methods only. C. Pure static methods only. D. Pure private methods.

Select an answer to check.

Answer: Interface methods with implementations (Java 8+).

Here, Interface methods with implementations (Java 8+). is the right choice. Backwards-compatible API additions. That is exactly the concept behind how is default methods best characterized in this context. The other options are either incomplete or contextually incorrect.

Q37. Which option best describes static methods on interfaces?

A. Pure abstract methods only. B. Default methods. C. Pure final methods. D. Utility methods on interfaces.

Select an answer to check.

Answer: Utility methods on interfaces.

In this case, Utility methods on interfaces. is correct. Java 8+. That is exactly the concept behind which option best describes static methods on interfaces in this context. The other options are either incomplete or contextually incorrect.

Q38. What is the primary purpose of static methods on interfaces?

A. Pure final methods. B. Pure abstract methods only. C. Utility methods on interfaces. D. Default methods.

Select an answer to check.

Answer: Utility methods on interfaces.

The best option here is Utility methods on interfaces.. Java 8+. That is exactly the concept behind what is the primary purpose of static methods in this context. The other options are either incomplete or contextually incorrect.

Q39. Which statement about static methods on interfaces is most accurate?

A. Pure final methods. B. Utility methods on interfaces. C. Default methods. D. Pure abstract methods only.

Select an answer to check.

Answer: Utility methods on interfaces.

For this question, Utility methods on interfaces. is correct. Java 8+. That is exactly the concept behind which statement about static methods on interfaces is in this context. The other options are either incomplete or contextually incorrect.

Q40. How is static methods on interfaces best characterized?

A. Utility methods on interfaces. B. Pure final methods. C. Default methods. D. Pure abstract methods only.

Select an answer to check.

Answer: Utility methods on interfaces.

Utility methods on interfaces. is the correct answer here. Java 8+. That is exactly the concept behind how is static methods on interfaces best characterized in this context. The other options are either incomplete or contextually incorrect.

Q41. Which option best describes composition over inheritance?

A. Pure aggregation only. B. Always use inheritance. C. Pure interface only. D. Prefer has-a over is-a.

Select an answer to check.

Answer: Prefer has-a over is-a.

Here, Prefer has-a over is-a. is the right choice. Reduces coupling. It fits the requirement in the prompt about which option best describes composition over inheritance. The other options are either incomplete or contextually incorrect.

Q42. What is the primary purpose of composition over inheritance?

A. Prefer has-a over is-a. B. Pure aggregation only. C. Pure interface only. D. Always use inheritance.

Select an answer to check.

Answer: Prefer has-a over is-a.

In this case, Prefer has-a over is-a. is correct. Reduces coupling. It fits the requirement in the prompt about what is the primary purpose of composition over. The other options are either incomplete or contextually incorrect.

Q43. Which statement about composition over inheritance is most accurate?

A. Prefer has-a over is-a. B. Pure interface only. C. Pure aggregation only. D. Always use inheritance.

Select an answer to check.

Answer: Prefer has-a over is-a.

The best option here is Prefer has-a over is-a.. Reduces coupling. It fits the requirement in the prompt about which statement about composition over inheritance is most. The other options are either incomplete or contextually incorrect.

Q44. How is composition over inheritance best characterized?

A. Always use inheritance. B. Pure aggregation only. C. Pure interface only. D. Prefer has-a over is-a.

Select an answer to check.

Answer: Prefer has-a over is-a.

For this question, Prefer has-a over is-a. is correct. Reduces coupling. It fits the requirement in the prompt about how is composition over inheritance best characterized. The other options are either incomplete or contextually incorrect.

Q45. Which option best describes the Liskov substitution principle?

A. Pure single responsibility. B. Pure dependency inversion. C. Pure interface segregation. D. Subtypes must be substitutable.

Select an answer to check.

Answer: Subtypes must be substitutable.

Subtypes must be substitutable. is the correct answer here. Behavioral subtyping. It fits the requirement in the prompt about which option best describes the liskov substitution principle. The other options are either incomplete or contextually incorrect.

Q46. What is the primary purpose of the Liskov substitution principle?

A. Subtypes must be substitutable. B. Pure dependency inversion. C. Pure single responsibility. D. Pure interface segregation.

Select an answer to check.

Answer: Subtypes must be substitutable.

Here, Subtypes must be substitutable. is the right choice. Behavioral subtyping. This is the most accurate statement for what is the primary purpose of the liskov. The other options are either incomplete or contextually incorrect.

Q47. Which statement about the Liskov substitution principle is most accurate?

A. Pure interface segregation. B. Subtypes must be substitutable. C. Pure single responsibility. D. Pure dependency inversion.

Select an answer to check.

Answer: Subtypes must be substitutable.

In this case, Subtypes must be substitutable. is correct. Behavioral subtyping. This is the most accurate statement for which statement about the liskov substitution principle is. The other options are either incomplete or contextually incorrect.

Q48. How is the Liskov substitution principle best characterized?

A. Pure dependency inversion. B. Subtypes must be substitutable. C. Pure single responsibility. D. Pure interface segregation.

Select an answer to check.

Answer: Subtypes must be substitutable.

The best option here is Subtypes must be substitutable.. Behavioral subtyping. This is the most accurate statement for how is the liskov substitution principle best characterized. The other options are either incomplete or contextually incorrect.

Q49. Which option best describes single responsibility?

A. Open/closed. B. Dependency inversion. C. LSP. D. One reason to change per class.

Select an answer to check.

Answer: One reason to change per class.

For this question, One reason to change per class. is correct. Cohesive design. This is the most accurate statement for which option best describes single responsibility. The other options are either incomplete or contextually incorrect.

Q50. What is the primary purpose of single responsibility?

A. Open/closed. B. One reason to change per class. C. Dependency inversion. D. LSP.

Select an answer to check.

Answer: One reason to change per class.

One reason to change per class. is the correct answer here. Cohesive design. This is the most accurate statement for what is the primary purpose of single responsibility. The other options are either incomplete or contextually incorrect.