Java Online Quiz


Advertisements

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 of the following is the default value of an instance variable?

A - null

B - 0

C - Depends upon the type of variable

D - Not assigned

Answer : C

Explaination

Instance variables are assigned default values based on their types. For example, int variable is assigned 0 and an object type variable is assigned null as default value.

Q 2 - What is the size of char variable?

A - 8 bit

B - 16 bit

C - 32 bit

D - 64 bit

Answer : B

Explaination

The char data type is represented by single 16-bit Unicode character.

Minimum value: '\u0000' (or 0)

Maximum value: '\uffff' (or 65,535)

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

A - 0.0d

B - 0.0f

C - 0

D - not defined

Answer : B

Explaination

float variable has default value of 0.0f if defined as an instance/static variable.

Answer : C

Explaination

Instance variables are variables within a class but outside any method. These variables are instantiated when the class is loaded.

Answer : A

Explaination

An applet is a Java program that runs in a Web browser.

Answer : A

Explaination

If a class has multiple functions by same name but different parameters, it is known as Method Overloading.

Answer : B

Explaination

Serialization is the process of writing the state of an object to a byte stream.

Answer : A

Explaination

Runtime polymorphism or dynamic method dispatch is a process in which a call to an overridden method is resolved at runtime rather than at compile-time. In this process, an overridden method is called through the reference variable of a superclass.

Q 10 - Which method must be implemented by all threads?

A - wait()

B - start()

C - stop()

D - run()

Answer : D

Explaination

All threads must implement the run() method.

java_questions_answers.htm
Advertisements