Java MCQ – Multiple Choice Questions and Answers – OOPs

This collection of Java Multiple Choice Questions and Answers (MCQs): Quizzes & Practice Tests with Answer focuses on “Java OOPs”.
 

1. Which of the following is not relevant to OOPS?

A Object and Class

B Encapsulation and Inheritance

C Enumerated type and Structure

D Constructor and Method

2. Can we overload constructor in derived class?

A Yes

B No

3. Which is an abstract data type?

A Double

B String

C Enum

D Class

4. Which keyword is used to inherit a class in Java?

A inherit

B implement

C extend

D extends

5. A private member of a class is accessible to ________________.

A only members of the same class

B members to the same package

C in subclass

D everywhere

6. In OOPs in Java, private, public & protected are ________________.

A Interfaces

B Classes

C Method signature

D Access Modifiers

7. Which doesn’t have a body?

A Class

B Abstract Method

C Method

D Interface

public abstract int my_method(int a, int b);

8. We can’t create an instance of ___________.

A Nested class

B Parent class

C Abstract class

D Anonymous class

9. Constructor can return a value ___________.

A True

B False

10. OOPs is invented by _____________.

A James Gosling

B Rasmus Lerdorf

C Alan Kay

D Tim Berners-Lee

11. Which Feature of OOP boost the code reusability?

A Encapsulation

B Polymorphism

C Inheritance

D Abstraction

12. Which of the following syntax used to create an object of Class in Java?

A Classname obj = new() Classname()

B Classname obj = new Classname;

C Classname obj = new Classname();

D None of the above

Classname obj = new Classname();

13. Which is used to create an Abstract class?

A Creating at least one member function as a pure virtual function

B Creating at least one member function as a virtual function

C Declaring as Abstract class using virtual keyword

D Declaring as Abstract class using static keyword

14. What is the output of the following Java code?

class Person 
{ 
    private int age; 
    
    private Person() 
    { 
        age = 24; 
    } 
} 

public class Test 
{ 
    public static void main(String[] args) 
    { 
        Person p = new Person(); 
        System.out.println(p.age); 
    } 
}

A 24

B Compilation error

C Runtime error

D None of the above

$javac Test.java
Test.java:16: error: Person() has private access in Person
        Person p = new Person(); 
                   ^
Test.java:17: error: age has private access in Person
        System.out.println(p.age); 
                            ^
2 errors

15. Which of the following is common class for exception handling?

A Try

B Object

C Exceptions

D Errors

16. What is the output of the following Java code?

class A 
{
  int data = 5;
  
  A() {
    data = 10;
  }
}

public class Test 
{
   public static void main(String args[]) 
   {
      A obj = new A();
      System.out.println(obj.data);
   }
}

A 5

B 10

C Compilation error

D Runtime error

17. Is there any compiler error?

class Point 
{
    int x, y; 
    
    public Point(int x, int y) 
    {    
        this.x = x;    
        this.y = y;  
    }
    
    public static void main(String args[]) 
    {
      Point obj = new Point();
    }
}

A True

B False

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