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Back to Question 10

Answer 9

C. 10

Explanation 9

A setter and a getter

This is a very simple program that uses a setter (modifier or mutator) method named setX to set the value 10 in a property named x that is stored in an instance variable named y in an object instantiated from the class named NewClass ..

The program also uses a getter (accessor) method named getX to get and display the value of the property named x . (Note that according to JavaBeans design patterns, the name of the property isunrelated to the name of variable in which the property value is stored.)

Back to Question 9

Answer 8

D. 5

Explanation 8

Hide your data and expose your methods

For reasons that I won't go into here, good object-oriented design principles state that in almost all cases where an instance variable is not declared to be final , it should be declared private . (A final variable behaves like a constant.)

What is private access?

When an instance variable is declared private , it is accessible only by methods of the class in which it is defined. Therefore, the only way that the"outside world" can gain access to a private instance variable is by going through an (usually public ) instance method of the object.

Accessor, modifier, mutator, setter, and getter methods

Historically, methods that have been defined for the purpose of exposing private instance variables to the outside world have been referred to as accessor and modifier methods. (Modifier methods are also sometimes called mutator methods.)

(Note that since the advent of Sun's JavaBeans Component design patterns, these methods have also come to be known as getter methods and setter methods indeference to the design-pattern naming conventions for the methods.)

A private instance variable with an initializer

The class named NewClass declares a private instance variable named x and initializes its value to 2, as shown in the following code fragment:

private int x = 2;

Two constructors

The class contains both a noarg constructor and a parameterized constructor as shown in the following fragment:

public NewClass(){ }//end constructorpublic NewClass(int x){this.x = x; }//end constructor

Calling the noarg constructor

If an object of the class is instantiated by calling the noarg constructor, the initial value of 2 remains intact, and that object contains an instancevariable with an initial value of 2.

Calling the parameterized constructor

If an object of the class is instantiated by calling the parameterized constructor, the initial value of 2 is overwritten by the value of the incomingparameter to the parameterized constructor. In this case, that value is 5, because the object is instantiated by the following code fragment that passesthe literal value 5 to the parameterized constructor. Thus, the initial value of the instance variable in that object is 5.

NewClass obj = new NewClass(5);

A getter method

Because the instance variable named x is private , it cannot be accessed directly for display by the code in the makeObj method of the Worker class. However, the NewClass class provides the following public getter or accessor method that can be used to get the value stored in the instance variable.

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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