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Kanti

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I am trying to explain Extend & Interface through anological way . Does these sound Correct !

I am trying to define the Extending and Interface definitions in an analogical way . Let me know if this will be OK ?


Extending Analogical Example

Parental Property Inheritance                  |      The concepts of Object Oriented
                                                         |      Inheritance  is also the same .
                                                         |
                                                         |
Inherited Parental Property  means you |      It  means that  you  have  all  the data variables and
had inherited every thing what your      |      Methods of the parent class. This enables you have
parents had without much hard work!   |      More  lines  of code with the required logic  without
                                                         |     much hard work.


If you are renovating your parents property        |  class MyPropertyClass extends ParentPropertyClass
by adding a  swimming pool  and car park    |  {
besides that  house  all you do is spend        |//You write  the body of swimming Pool;
money  to build only  for  these two  things,  |   //You write the body  of Car Park;
so you  save  money by not building a house.|  // You need not write about the house as you are
So  if you come from aKings family you              |  //extending your  parents house;
could inherit all your  Parents,Grand Parents |   }
Etc. If you  destroy the property you   have   |
nothing   and  in  in   JAVA it is called           |
Method Over-ridding.                                  |
                                     
      
                                                
                                                                Even JAVA there is no limit in the number  of
                                                                extensions  but  remember each class can extend
                                                               only one  super class  at  a time as JAVA does not
                                                                support Multiple inheritance



INTERFACE EXAMPLE
 
            AIRPORT CHECK-IN                                |      CLIENT CHECK-IN.
                                                                        |
When  you  want to  Fly out to another               |   Even  in  OO  Technique  the Bean  
country you  can   board  the  Aircraft                    |  Classes are not directly Exhibited to the
only  when you show  your passports which          |  Clients but uses an Interface  
has your Signature, Expiry Date    etc.                    | which has the method structure  
This means  that the CLERK identifies you                | i.e  method signatures  of the Class  
through the Passport as she sees Your                 | with no  logic   or  you  can say            
 image and Signature .                                       |  Interface has the skeleton of the Class.
                                                                        |  The Clients talk to the bean Class
                                                                        | through  the interface.
                  


                                                                        | So analogically  if you want to compare  
                                                                        |  with the Airport Check-in     example   the
CLERK LOOKS INTO PASSPORTs TO KNOW           | Clerk will be your client ,The passport  which
                                           THE PASSENGER     |  identifies you will be  the interface as it has
                                                                        |  your structure i.e  your PHOTO  and
                                                                        | Signature and you  will  represent  
CLIENT LOOKS INTO  INTERFACE  TO KNOW              |  the  bean .So without
                                               BEAN CLASS       | Passport  you are  not  allowed  to  
                                                                        |  board  the   Aircraft  and   with   out
                                                                        |  INTERFACE the  BEAN will not do anything
                                                                        |  for you .
                              

                                                                         NOTE:
                                                                        There will no implementation in an  
                                                                        INTERFACE .So INTERFACE is like having the
                                                                        PHOTO of the Class.
      
Avatar of sciuriware
sciuriware

No I don't like this story. It's too synthetic and too long. Try this:

In a hospital: everybody in a long white coat and a stethoscope is taken for a doctor:  INTERFACE, the patients sight.
In fact it takes many years to study and to promote to be a surgeon: EXTEND, the administration's sight.

I am a hired programmer and sit beside the customers employees.
I'm an INTERFACE (to the team) they are only intereseted in my skill.
The person right to me is a CLASS: he/she is an employee and will be promoted on success (EXTENSION).

From sheer frustration, ;JOOP!

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sbockelman

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