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class Base{ public void test(){System.out.print("Base "); }//end test()}//end class Base interface X{public void test(); }//end Xinterface Y{ public void test();}//end Y class A extends Base implements X,Y{public void test(){ System.out.print("A ");}//end test() }//end class A

Classes A and B extend Base and implement X and Y

The code in the following fragment defines two classes, named A and B , each of which extends Base , and each of which implements both interfaces X and Y . Each class provides a concrete definition for the method named test , with each class providing a different definition.

class A extends Base implements X,Y{ public void test(){System.out.print("A "); }//end test()}//end class A class B extends Base implements X,Y{public void test(){ System.out.print("B ");}//end test() }//end class B

Override inherited method and define interface method

Each of the methods named test in the above fragment serves not only to override the method inherited from the class named Base , but also to satisfy the requirement to define the methods declared in theimplemented interfaces named X and Y . (This can also be thought of as overriding an inherited abstract method from an interface.)

Store object's references as type Base and call test method

Finally, the code in the following fragment declares a reference variable of the type Base . Objects respectively of the classes Base , A , and B are instantiated and stored in the reference variable. Then the method named test is called on each of the references in turn.

void doIt(){ Base myVar = new Base();myVar.test(); myVar = new A();myVar.test(); myVar = new B();myVar.test(); System.out.println("");}//end doIt() }// end class Worker

As you probably expected, this causes the following text to appear on the screen:

Base A B

Back to Question 9

Answer 8

C. A-intfcMethodX B-intfcMethodX

Explanation 8

Similar to previous two programs

This program is very similar to the programs in Question 6 and Question 7 . The program is Question 6 exposed a specific type mismatch problem. The program in Question 7 provided one solution to the problem.

A different solution

The following fragment illustrates a different solution to the problem.

void doIt(){ X[]myArray = new X[2];myArray[0] = new A();myArray[1] = new B();for(int i=0;i<myArray.length;i++){ myArray[i].intfcMethodX(); }//end for loopSystem.out.println(""); }//end doIt()

An array object of the interface type

In this case, rather than to declare the array object to be of type Object , the array is declared to be of the interface type X .

This is a less generic container than the one declared to be of type Object . Only references to objects instantiated from classes that implement the X interface, or objects instantiated from subclasses of those classes can be stored in the container. However, this is often adequate.

What methods can be called?

Since the references are stored as the interface type, any method declared in or inherited into the interface can be called on the references stored in the container.Of course, the objects referred to by those references must provide concrete definitions of those methods or the program won't compile.

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
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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