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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

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
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
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
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
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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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