This set of Java Multiple Choice Questions & Answers (MCQs) focuses on “OOPs”.
1. Which of the following is not OOPS concept in Java?
a) Inheritance
b) Encapsulation
c) Polymorphism
d) Compilation
View Answer
Explanation: There are 4 OOPS concepts in Java. Inheritance, Encapsulation, Polymorphism and Abstraction.
2. Which of the following is a type of polymorphism in Java?
a) Compile time polymorphism
b) Execution time polymorphism
c) Multiple polymorphism
d) Multilevel polymorphism
View Answer
Explanation: There are two types of polymorphism in Java. Compile time polymorphism (overloading) and runtime polymorphism (overriding).
3. When does method overloading is determined?
a) At run time
b) At compile time
c) At coding time
d) At execution time
View Answer
Explanation: Overloading is determined at compile time. Hence, it is also known as compile time polymorphism.
4. When Overloading does not occur?
a) More than one method with same name but different method signature and different number or type of parameters
b) More than one method with same name, same signature but different number of signature
c) More than one method with same name, same signature, same number of parameters but different type
d) More than one method with same name, same number of parameters and type but different signature
View Answer
Explanation: Overloading occurs when more than one method with same name but different constructor and also when same signature but different number of parameters and/or parameter type.
5. Which concept of Java is a way of converting real world objects in terms of class?
a) Polymorphism
b) Encapsulation
c) Abstraction
d) Inheritance
View Answer
Explanation: Abstraction is the concept of defining real world objects in terms of classes or interfaces.
6. Which concept of Java is achieved by combining methods and attribute into a class?
a) Encapsulation
b) Inheritance
c) Polymorphism
d) Abstraction
View Answer
Explanation: Encapsulation is implemented by combining methods and attribute into a class. The class acts like a container of encapsulating properties.
7. What is it called if an object has its own lifecycle and there is no owner?
a) Aggregation
b) Composition
c) Encapsulation
d) Association
View Answer
Explanation: It is a relationship where all objects have their own lifecycle and there is no owner. This occurs where many to many relationships are available, instead of one to one or one to many.
8. What is it called where child object gets killed if parent object is killed?
a) Aggregation
b) Composition
c) Encapsulation
d) Association
View Answer
Explanation: Composition occurs when child object gets killed if parent object gets killed. Aggregation is also known as strong Aggregation.
9. What is it called where object has its own lifecycle and child object cannot belong to another parent object?
a) Aggregation
b) Composition
c) Encapsulation
d) Association
View Answer
Explanation: Aggregation occurs when objects have their own life cycle and child object can associate with only one parent object.
10. Method overriding is combination of inheritance and polymorphism?
a) True
b) false
View Answer
Explanation: In order for method overriding, method with same signature in both superclass and subclass is required with same signature. That satisfies both concepts inheritance and polymorphism.
Sanfoundry Global Education & Learning Series – Java Programming Language.
To practice all areas of Java language, here is complete set of 1000+ Multiple Choice Questions and Answers.
- Get Free Certificate of Merit in Java Programming
- Participate in Java Programming Certification Contest
- Become a Top Ranker in Java Programming
- Take Java Programming Tests
- Chapterwise Practice Tests: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
- Chapterwise Mock Tests: Chapter 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
- Buy Java Books
- Practice Information Technology MCQs
- Practice Programming MCQs
- Buy Programming Books
- Apply for Information Technology Internship
