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nested interface

 
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Hello,
I am not sure if my question belongs to the advance forum but I am hoping to get some good advices here..
I have seen the following section in my code base .


Isn't this same as -

what is the advantage of using this kind of nested interface? Will C have the properties of A and B? What does C implements A.B mean exactly??
Kindly advise.
 
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Isn't this same as ...


No; implementing an interface is not the same thing as extending a class.

What does C implements A.B mean exactly?


It means that C implements the A.B interface--there's no difference between implementing an interface and implementing a nested interface--they're both just interfaces.
 
Hari priya
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Thanks David!

Can you also answer these questions-

what is the advantage of using this kind of nested interface? Will C have the properties of A and B?
 
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i dont know what is the advantage of this kind of interface.

Coming to your 2nd question : whether C has the properties of A and B ?

try below program

 
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Hari priya wrote:what is the advantage of using this kind of nested interface? Will C have the properties of A and B?


If interface B is only used in combination with interface A you could use a nested interface. This is an indication that interface B belongs somehow to interface A. Map.Entry is one such example.

C will have no combination with A anymore; interface B is implicitly static, and therefore the only real link between A and B is the namespace. A Map.Entry implementation does not need to know anything about the Map interface. For instance, java.util.AbstractMap.SimpleEntry is a static nested class has just one link to AbstractMap - and that's a static utility method that could just as well been omitted:
 
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