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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.

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?

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 byte variable?

Answer : A

Explaination

Byte 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 - Inheritance represents

A - HAS-A relationship.

B - IS-A relationship.

Answer : B

Explaination

Inheritance represets IS-A relationship providing code reusablity . Consider the following statement: Circle is a Shape. Here Shape is super class and Circle is a child class extends the super class Shape.

Q 6 - Can be constructor be made private?

A - True.

B - False.

Answer : A

Explaination

Yes, class with private constructor can not instantiated using new keyword.

Q 7 - What is function overriding?

A - If a subclass uses a method that is already provided by its parent class, it is known as Method Overriding.

B - If a subclass provides a specific implementation of a method that is already provided by its parent class, it is known as Method Overriding.

C - Both of the above.

D - None of the above.

Answer : B

Explaination

If a subclass provides a specific implementation of a method that is already provided by its parent class, it is known as Method Overriding.

Q 8 - What happens when thread's sleep() method is called?

A - Thread returns to the ready state.

B - Thread returns to the waiting state.

C - Thread starts running.

D - None of the above.

Answer : B

Explaination

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

Q 9 - Deletion is faster in LinkedList than ArrayList.

A - True.

B - False.

Answer : A

Explaination

Deletion in linked list is fast because it involves only updating the next pointer in the node before the deleted node and updating the previous pointer in the node after the deleted node.

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

A - serializable

B - comparable

C - cloneable

D - none of the above.

Answer : A

Explaination

serializable is a marker interface.

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