<< Chapter < Page Chapter >> Page >
interface X{ public void intfcMethodX();}//end X

Class A extends Base and implements X

The next fragment shows the definition of a class named A that extends Base and implements X .

class A extends Base implements X{ public void inherMethod(){System.out.print( " A-inherMethod ");}//end inherMethod()public void intfcMethodX(){ System.out.print("A-intfcMethodX "); }//end intfcMethodX()}//end class A

Defining interface method

Because the class named A implements the interface named X , it must provide a concrete definition of all the methods declared in X .

In this case, there is only one such method. That method is named intfcMethodX . A concrete definition for the method is provided in the class named A .

Class B also extends Base and implements X

The next fragment shows the definition of another class (named B ), which also extends Base and implements X .

class B extends Base implements X{ public void inherMethod(){System.out.print( " B-inherMethod ");}//end inherMethod()public void intfcMethodX(){ System.out.print("B-intfcMethodX "); }//end intfcMethodX()}//end class B

Defining the interface method

Because this class also implements X , it must also provide a concrete definition of the method named intfcMethodX .

Different behavior for interface method

However (and this is extremely important) , there is no requirement for this definition of the method to match the definition in the class named A , or to match the definition in any other class that implements X .

Only the method signature for the method named intfcMethodX is necessarily common among all the classes that implement the interface.

The definition of the method named intfcMethodX in the class named A is different from the definition of the method having the same name in the class named B .

The interesting behavior

The interesting behavior of this program is illustrated by the code in the following fragment.

void doIt(){ X myVar1 = new A();myVar1.intfcMethodX();X myVar2 = new B(); myVar2.intfcMethodX();System.out.println(""); }//end doIt()

Store object's references as interface type X

The code in the above fragment causes one object to be instantiated from the class named A , and another object to be instantiated from the class named B .

The two object's references are stored in two different reference variables, each declared to be of the type of the interface X .

Call the interface method on each reference

A method named intfcMethodX is called on each of the reference variables. Despite the fact that both object's references are storedas type X , the system selects and calls the appropriate method, (as defined by the class from which each object was instantiated) , on each of the objects. This causes the following text to appear on the screen:

A-intfcMethodX B-intfcMethodX

No subclass-superclass relationship exists

Thus, the use of an interface makes it possible to call methods having the same signatures on objects instantiated from different classes, without anyrequirement for a subclass-superclass relationship to exist among the classes involved.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
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.
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
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
characteristics of micro business
for teaching engĺish at school how nano technology help us
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
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

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
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?