Java Online Quiz


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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 - Static functions can be accessed using null reference.

A - True

B - False

Answer : A

Explaination

True, Static functions can be accessed via class name or via null reference.

Q 2 - What is the size of long variable?

A - 8 bit

B - 16 bit

C - 32 bit

D - 64 bit

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 String variable?

A - ""

B - ''

C - null

D - not defined

Answer : C

Explaination

String variable has default value of null if defined as an instance/static variable.

Answer : B

Explaination

String object is immutable so that once it is created a String object cannot be changed. Since String is immutable it can safely be shared between many threads which are considered very important for multithreaded programming.

Q 5 - A class always has a default constructor.

A - True

B - False

Answer : B

Explaination

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

Answer : D

Explaination

Final classes are created so the methods implemented by that class cannot be overridden. It can't be inherited. These classes are declared final.

Answer : D

Explaination

A thread can enter the waiting state by invoking its sleep() method, by blocking on IO, by unsuccessfully attempting to acquire an object's lock, or by invoking an object's wait() method. It can also enter the waiting state by invoking its (deprecated) suspend() method.

Q 9 - Can constructor be inherited?

A - True.

B - False.

Answer : B

Explaination

No, constructor cannot be inherited.

Q 10 - which operator is considered to be with highest precedence?

A - () , []

B - =

C - ?:

D - %

Answer : A

Explaination

Postfix operators i.e () [] . is at the highest precedence.

java_questions_answers.htm
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