Java MCQs 50 Questions Set for your Exam

#1. Which collection class is synchronized?

ArrayList

HashMap

Vector

HashSet

#2. What is the size of a float variable in Java?

4 bytes

8 bytes

2 bytes

1 bytes

#3. Which of the following is not a valid wrapper class in Java?

Integer

Character

Double

string

#4. What is the output of ‘System.out.println(10 + “20”);’?

1020

Error

null

#5. What is the default value of a boolean variable in Java?

true

false

#6. What is the output of “System.out.println(2 + 3 * 4);”?

#7. What is the purpose of the “static” keyword in Java?

To make a variable constant.

To associate a member with a class rather than an object.

To make a class final.

To prevent method overriding.

#8. Which of these is not a Java access modifier?

public

private

protected

package

#9. What is the default access modifier in Java?

private

public

protected

package-private

#10. Which of the following is true about Java?

Java supports pointers.

Java uses automatic memory management.

Java code is compiled to machine code directly.

Java programs are not portable.

#11. Which of these is a valid method declaration in Java?

public void myMethod();

public void myMethod()

public void myMethod{}

public void myMethod[];

#12. How can you define a constant in Java?

Using "static final"

Using "const"

Using "#define"

Using "immutable"

#13. Which keyword is used to stop the execution of a loop?

exit

break

stop

terminate

#14. Which interface is used to implement a collection that does not allow duplicate elements?

Map

List

Set

Queue

#15. What is the result of “true && false” in Java?

True

False

null

Error

#16. Which of the following statements is true about constructors?

Constructors have a return type.

Constructors can be inherited.

Constructors are called explicitly.

Constructors are invoked when an object is created.

#17. What is the result of “3 >> 1” in Java?

#18. What is the output of “System.out.println(5 / 2);”?

2.5

2.0

Error

#19. Which method is used to start a thread in Java?

execute()

start()

run()

begin()

#20. Which class is used to take input from the user in Java?

Scanner

BufferedReader

InputStreamReader

All of the above

#21. What is the purpose of the “break” statement in Java?

To terminate the program.

To exit a loop or switch statement.

To pause execution temporarily.

To skip an iteration in a loop.

#22. What is the default value of an int variable in Java?

null

undefined

#23. Which exception is thrown when dividing by zero in Java?

ArithmeticException

NullPointerException

IOException

NumberFormatException

#24. Which of these is used to handle exceptions in Java?

catch

throw

try

All of the above

#25. Which of the following is not part of the Java runtime environment?

JVM

JDK

JRE

Garbage Collector

#26. Which of these methods is used to read a character from standard input in Java?

System.in.read()

Scanner.nextChar()

BufferedReader.readChar()

System.read()

#27. Which of these is not a reserved keyword in Java?

goto

null

static

assert

#28. Which class is used to handle file operations in Java?

FileReader

File

FileHandler

FileStream

#29. What does the “final” keyword in Java do?

Prevents inheritance of a class.

Prevents a method from being overridden.

Prevents a variable from being reassigned.

All of the above.

#30. What is the purpose of the “super” keyword in Java?

To invoke the current class constructor.

To invoke the parent class constructor.

To define constants.

To stop inheritance.

#31. What is the parent class of all classes in Java?

Object

Class

Base

Super

#32. Which of these is not an exception handling keyword?

throw

try

finally

finalize

#33. How do you declare an array in Java?

int array[] = new int[];

int array = new int[];

int[] array = new int[];

All of the above

#34. What does the ‘this’ keyword refer to?

Current object

Parent class

Constructor

Package

#35. Which of these is not a valid method of the Math class?

abs()

round()

parseInt()

max()

#36. What is the default value of a reference variable in Java?

null

undefined

#37. What is the extension of compiled Java files?

.java

.exe

.class

.obj

#38. Which operator is used to concatenate strings in Java?

#39. How do you declare a class as abstract in Java?

By using the "final" keyword.

By using the "abstract" keyword.

By not implementing all methods in the class.

By declaring all methods as "static".

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

implements

extends

inherit

super

#41. What is the purpose of the “volatile” keyword?

To prevent method overriding.

To ensure a variable's value is always read from memory.

To mark a variable as constant.

To stop thread execution.

#42. What is a correct way to create an object in Java?

ClassName obj = ClassName();

ClassName obj = new ClassName();

ClassName obj = create ClassName();

ClassName obj();

#43. What is the purpose of the “instanceof” keyword?

To check the type of an object.

To create a new object.

To cast an object to a subclass.

To initialize a variable.

#44. Which of the following is not a primitive data type in Java?

int

float

String

Char

#45. What is the result of “Math.sqrt(16)”?

Error

#46. Which of these is not a feature of the Java programming language?

Platform Independence

Multithreaded

Procedural

Secure

#47. Which package contains the Random class?

java.io

java.util

java.math

java.lang

#48. Which of the following is not a feature of Java?

Object-Oriented

Platform-Dependent

Secure

Multithreaded

#49. What is the correct way to import a package in Java?

include package;

import package.;

package include;

use package;

#50. How many threads can run simultaneously in a single Java program?

Unlimited

Depends on the JVM and OS

Finish

Results

Congratulations

Better Luck Next Time

Java MCQs 50 Questions Set

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Abhijeet

My name is Abhijeet. I have more than 5 years of experience in the real estate industry and also hold an MBA degree. I am quite knowledgeable and expert in this field. I like to help my clients make correct and informed decisions and hence I write every article with deep research and accuracy. Whether you want to buy property, sell it or invest, all my articles will help you understand the complexities of real estate easily and take decisions with confidence.

Java MCQs 50 Questions Set