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 - What is the size of byte variable?

A - 8 bit

B - 16 bit

C - 32 bit

D - 64 bit

Answer : A

Explaination

The byte data type is represented by an 8-bit signed two's complement integer.

Minimum value: -128

Maximum value: 127

Q 2 - Can we have two public classes in one java file?

A - True

B - False

Answer : B

Explaination

No, a java file can contain only one public class.

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.

Answer : B

Explaination

An immutable object can't be changed once it is created. String objects are immutable.

Answer : B

Explaination

A class consist of Local variable, instance variables and class variables.

Answer : A

Explaination

Method Overloading is example of static binding.

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 a top level class be private or protected?

A - True.

B - False.

Answer : B

Explaination

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

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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