Interfaces

[Kavana Krishnappa]

Hi,

Can you tel me more about interfaces & in what applications can we implement that concept..

[Corvin]

Have a look at this page:
Interface (Java - Wikipedia, the free encyclopedia)

[staykovmarin]

Interfaces can be used to tell in implementing class that it NEEDS to have those methods implemented. Since java does not support multiple inheritance (ie. extend more than one object) it is usefull to tell something it needs to conform to a certain standard.

Basicly, lets say you create an interface with a single method void called foo(). In interfaces, methods cannot have bodies, so it will look something like:

public interface FooInterface {
	public void foo();
}

Then in your class you can do:

public class BarClass implements FooInterface {
          
}

If you tried to compile something like this it will give you an error, because you need the foo() method.

public class BarClass implements FooInterface {
          public void foo() {
                    // blah
          }
}

I use interfaces mostly when i am creating a complicated class/sublass structure, and want all my code to conform to a certain standard.
A plugin system would be an example of using interfaces.

[Kavana Krishnappa]

can you suggest me any small real time application on which i can do a project in core Java..

[JavaBean]

Kavana, try creating a new thread instead of spamming old threads. In that way, you can find better answers if you select appropriate thread titles.

[Kavana Krishnappa]

It was given as,
A class which implements an interface must either implement all methods in the interface, or be an abstract class.
- since a class which implements an interface has to implement all the methods of that interface, is it not a disadvantage that it has to implement all methods even if we want only some methods to be implemented..

[Kavana Krishnappa]

i did not understand what you told sir.. did you mean that i should post my queries directly than just replying to their replies.. i am new to this forum so am not much familiar how to use..

[JavaBean]

did you mean that i should post my queries directly than just replying to their replies..

Yes! Your query below is not related to this thread. Go to appropriate forum index and click "New Thread" button, instead of clicking to the "Post Reply" button here.

can you suggest me any small real time application on which i can do a project in core Java..