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?

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 - What is the size of float variable?

Answer : C

Explaination

The float data type is represented by single-precision 32-bit IEEE 754 floating point.

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

Answer : B

Explaination

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

Q 4 - Which of the following is false about String?

A - String is immutable.

B - String can be created using new operator.

C - String is a primary data type.

D - None of the above.

Answer : C

Explaination

String is a object.

Q 5 - What is Abstraction?

A - Abstraction is a technique to define different methods of same type.

B - Abstraction is the ability of an object to take on many forms.

C - It refers to the ability to make a class abstract in OOP.

D - None of the above.

Answer : C

Explaination

It refers to the ability to make a class abstract in OOP. It helps to reduce the complexity and also improves the maintainability of the system.

Q 6 - What is Set Interface?

A - Set is a collection of element which contains elements along with their key.

B - Set is a collection of element which contains hashcode of elements.

C - Set is a collection of element which cannot contain duplicate elements.

D - Set is a collection of element which can contain duplicate elements.

Answer : C

Explaination

Set is a collection of element which cannot contain duplicate elements. The Set interface contains only methods inherited from Collection and adds the restriction that duplicate elements are prohibited.

Q 7 - Dynamic binding uses which information for binding?

C - Both of the above.

D - None of the above.

Answer : B

Explaination

Dynamic binding uses object information for binding.

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 - Is it necessary that each try block must be followed by a catch block?

Answer : B

Explaination

It is not necessary that each try block must be followed by a catch block. It should be followed by either a catch block or a finally block.

Q 10 - Which of the following is a marker interface?

A - serializable

D - none of the above.

Answer : A

Explaination

serializable is a marker interface.

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