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Java Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to Core Java. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - What is correct syntax for main method of a java class?

A - public static int main(String[] args)

B - public int main(String[] args)

C - public static void main(String[] args)

D - None of the above.

Answer : C

Explaination

Correct syntax is public static void main(String[] args).

Q 2 - What is the size of long variable?

Answer : D

Explaination

The long data type is represented by 64-bit two's complement integer.

Minimum value: -263

Maximum value: 263-1

Q 3 - What is the default value of byte variable?

Answer : A

Explianation

Byte variable has default value of 0 if defined as an instance/static variable.

Q 4 - Which of the following is true about public access modifier?

A - Variables, methods and constructors which are declared public can be accessed by any class.

B - Variables, methods and constructors which are declared public can be accessed by any class lying in same package.

C - Variables, methods and constructors which are declared public in the superclass can be accessed only by its child class.

D - None of the above.

Answer : A

Explaination

Public access modifier is used to make variables, methods and constructors accessible to any class.

Q 5 - A class always has a default constructor.

Answer : B

Explaination

It is not mandatory to have a default constructor in a class.

Q 6 - Can be constructor be made private?

Answer : A

Explaination

Yes, class with private constructor can not instantiated using new keyword.

Q 7 - When static binding occurs?

A - Static binding occurs during Compile time.

B - Static binding occurs during load time.

C - Static binding occurs during runtime.

D - None of the above.

Answer : A

Explaination

Static binding occurs during Compile time.

Q 8 - What are Wrapper classes?

A - These are classes that allow primitive types to be accessed as objects.

B - These are classes that wraps functionality of an existing class.

C - Both of the above.

D - None of the above.

Answer : A

Explaination

These are classes that allow primitive types to be accessed as objects. Example: Integer, Character, Double, Boolean etc.

Q 9 - Can a top level class be private or protected?

Answer : B

Explaination

No, a top level class can not be private or protected. It can have either "public" or no modifier.

Q 10 - What is currentThread()?

A - It is a Thread public static method used to obtain a reference to the current thread.

B - It is a thread's instance method used to get thread count.

C - It is a object's public static method used obtain a reference to the current thread.

D - It is a object's instance method used to get thread count.

Answer : A

Explaination

currentThread() is a public static method of Thread class used to obtain a reference to the current thread.

java_questions_answers.htm

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