• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Tim Cooke
  • paul wheaton
  • Jeanne Boyarsky
  • Ron McLeod
Sheriffs:
  • Paul Clapham
  • Liutauras Vilda
  • Devaka Cooray
Saloon Keepers:
  • Tim Holloway
  • Roland Mueller
Bartenders:

Extend an Interface (Not implement)?

 
Ranch Hand
Posts: 92
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I noticed in Java 6 API that the interface "Set" extends another interface "Collection".

I just thought you can't extend an interface but should be IMPLEMENTED ONLY.

Can anyone clarify this java rule?

Thanks a lot!
 
Ranch Hand
Posts: 400
Hibernate Spring Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Dear Erap Estrada,

java.util.Set is also an interface and an interface can extends another interface.
 
Ranch Hand
Posts: 494
Eclipse IDE Postgres Database Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Of course, the Interface can extends the other interface, but we can only describe methods in each interface (Superclass interface and Subclass interface)..
 
Ranch Hand
Posts: 504
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Leonardo Carreira wrote:Of course, the Interface can extends the other interface, but we can only describe methods in each interface (Superclass interface and Subclass interface)..



we don't describe methods in an interface but only declare them.
 
Leonardo Carreira
Ranch Hand
Posts: 494
Eclipse IDE Postgres Database Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Thanks Neha, yes, its what i mean, i was wrong to use "describe" word..
sorry, perhaps it because my English language inadequacy..

Thanks..
 
Sheriff
Posts: 67753
173
Mac Mac OS X IntelliJ IDE jQuery TypeScript Java iOS
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Think about it for a moment. Does the second interface really implement the methods of the first? Can you instantiate the second interface?

Of course not. So the second interface doesn't implement the first, rather it extends it, but remains abstract. So it makes perfect sense that the second interface extends the first.
 
Normally trees don't drive trucks. Does this tiny ad have a license?
Smokeless wood heat with a rocket mass heater
https://woodheat.net
reply
    Bookmark Topic Watch Topic
  • New Topic