• 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
  • Jeanne Boyarsky
  • Ron McLeod
  • Paul Clapham
  • Liutauras Vilda
Sheriffs:
  • paul wheaton
  • Rob Spoor
  • Devaka Cooray
Saloon Keepers:
  • Stephan van Hulst
  • Tim Holloway
  • Carey Brown
  • Frits Walraven
  • Tim Moores
Bartenders:
  • Mikalai Zaikin

To Reference the Interface Or the Class That Implements the Interface?

 
Ranch Hand
Posts: 1309
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I have some methods defined in an interface UserDAO; something like:

and I have a class MySQLUserDAO that implements UserDAO.
If I want to access the method findUserPassword( String username ) from a class called UserService, I should access the interface or the class that implements the interface? For example, which one is correct:

or

[ November 24, 2003: Message edited by: JiaPei Jen ]
 
Ranch Hand
Posts: 61
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi,
Generally, we will create only a reference to an interface. Your code,

will not compile because, you are trying to instantiate an interface, which is not possible.
May be, you can use it this way,

Thanks,
Uma.
 
Ranch Hand
Posts: 3178
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Interfaces are acting as superclasses of the implementing class, because Java doesn't allow multiple inheritence... So the usage of interfaces is devoloped in Java...
 
Can you smell this for me? I think this tiny ad smells like blueberry pie!
a bit of art, as a gift, the permaculture playing cards
https://gardener-gift.com
reply
    Bookmark Topic Watch Topic
  • New Topic