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Java Classes and Objects

Here are 10 essential multiple-choice questions on Java Classes and Objects, covering key concepts.

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Question 1

Which of the following is NOT an OOP concept in Java?

Encapsulation
Inheritance
Polymorphism
Compilation

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Question 2

What is an object in Java?

A class template
An instance of a class
A function
A primitive data type

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Question 3

What is the primary purpose of a constructor in Java?

To allocate memory
To initialize an object
To call methods
To delete objects

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Question 4

Which keyword is used to create an object in Java?

class
this
new
void

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Question 5

What will be the output of the following code?

Java

class Test {
    int x;
}
public class Main {
    public static void main(String[] args) {
        Test t = new Test();
        System.out.println(t.x);
    }
}

0
null
Compilation Error
Runtime Exception

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Question 6

What is encapsulation in Java?

Wrapping data and methods into a single unit
Allowing multiple forms of a method
Inheriting properties from a parent class
Overriding methods from an interface

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Question 7

What will be the output of the following code?

Java

class Car {
    String model;
}
public class Main {
    public static void main(String[] args) {
        Car c = null;
        System.out.println(c.model);
    }
}

null
Compilation Error
NullPointerException
Empty String

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Question 8

Which of the following is TRUE about constructors?

Constructors must always have a return type
Constructors cannot be overloaded
Constructors can have parameters
A class cannot have multiple constructors

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Question 9

What will be the output of the following code?

Java

class Example {
    Example() {
        System.out.println("Constructor called");
    }
}
public class Main {
    public static void main(String[] args) {
        Example e = new Example();
    }
}

Constructor called
No output
Compilation Error
Runtime Error

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Question 10

What is the correct way to define a class in Java?

public Example {}
class Example {}
void Example {}
object Example {}

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