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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.

Questions and Answers

Q 1 - What of the following is the default value of an instance variable?

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 int variable?

Answer : C

Explaination

The int data type is represented by 32-bit signed two's complement integer,

Minimum value: -231

Maximum value: 231-1

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

D - not defined

Answer : B

Explaination

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

Q 4 - Which of the following stands true about default modifier of class members?

A - By default, variables, methods and constructors can be accessed by subclass only.

B - By default, variables, methods and constructors can be accessed by any class lying in any package.

C - By default, variables, methods and constructors can be accessed by any class lying in the same package.

D - None of the above.

Answer : C

Explaination

By default, variables, methods and constructors can be accessed by any class lying in the same package.

Q 5 - What is an Interface?

A - An interface is a collection of abstract methods.

B - Interface is an abstract class.

C - Interface is an concrete class.

D - None of the above.

Answer : C

Explaination

An interface is a collection of abstract methods. A class implements an interface, thereby inheriting the abstract methods of the interface.

Q 6 - Can be constructor be made final?

Answer : B

Explaination

No, this is not possible.

Q 7 - What is function overloading?

A - Methods with same name but different parameters.

B - Methods with same name but different return types.

C - Methods with same name, same parameter types but different parameter names.

D - None of the above.

Answer : A

Explaination

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

Q 8 - What happens when thread's yield() 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 : A

Explaination

When a task invokes its yield() method, it returns to the ready state.

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 - When finally block gets executed?

A - Always when try block get executed, no matter exception occured or not.

B - Always when a method get executed, no matter exception occured or not.

C - Always when a try block get executed, if exception do not occur.

D - Only when exception occurs in try block code.

Answer : A

Explaination

Always when try block get executed, no matter exception occured or not.

java_questions_answers.htm

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