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 - Which of the following is not a keyword in java?

A - static

B - Boolean

C - void

C - private

Answer : B


Boolean is a class and is not a keyword.

Q 2 - What is the size of double variable?

A - 8 bit

B - 16 bit

C - 32 bit

D - 64 bit

Answer : D


The double data type is represented by double-precision 64-bit IEEE 754 floating point.

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

A - 0

B - 0.0

B - null

B - undefined

Answer : A


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

Answer : B


Polymorphism is the ability of an object to take on many forms. The most common use of polymorphism in OOP occurs when a parent class reference is used to refer to a child class object.

Answer : A


Variables defined inside methods, constructors or blocks are called local variables. The variable will be declared and initialized within the method and it will be destroyed when the method has completed.

Q 6 - Composition represents

A - HAS-A relationship.

B - IS-A relationship.

Answer : A


Holding the reference of the other class within some other class is known as composition. It represents a HAS-A relationship. For example, a Student has a Pen. Here Student class has Pen as its instance variable.

Q 7 - Dynamic binding uses which information for binding?

A - type.

B - object.

C - Both of the above.

D - None of the above.

Answer : B


Dynamic binding uses object information for binding.

Answer : B


When a task invokes its sleep() method, it returns to the waiting state.

Q 9 - Can constructor be inherited?

A - True.

B - False.

Answer : B


No, constructor cannot be inherited.

Q 10 - This is the parent of Error and Exception classes.

A - Throwable

B - Catchable

C - MainError

D - MainException

Answer : A


Throwable is the parent of both Error and Exception class.