wood burning stoves*
The moose likes Beginning Java and the fly likes How Interface is different from Abstract Class incase of Inheritence Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Beginning Java
Bookmark "How Interface is different from Abstract Class incase of Inheritence" Watch "How Interface is different from Abstract Class incase of Inheritence" New topic
Author

How Interface is different from Abstract Class incase of Inheritence

jayaprakash kaluva
Greenhorn

Joined: Aug 01, 2012
Posts: 4
Sub class of a Parent class will inheret all the public and protected members .will an implementing class of an interface inheret the members of Interface ?

My doubt is why can't we declare protected members in interface ?

if a class which is implementing an interface inherets the fields ,we can declare the protected fields and we can acess them.
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 40052
    
  28
Welcome to the Ranch (again)

I don’t like the term parent class; say superclass. I know people will disagree with me, however.
You cannot override fields, only instance methods. If you try creating fields in a class which have the same name as fields in superclasses or interfaces, you end up with two fields. I think it is called hiding; look at this FAQ.
Rule of thumb: make all fields private except those used as constants; those should be public static final.
Rule of thumb: never try to use a field in a subclass. Use public (or protected) methods which use those fields.
Rule of thumb: you can override instance methods. But read Joshua Bloch’s Effective Java or another good book before you try it.

This is what such a public method might look like:-By using the superclass field and its public method you get any access to i that you need.
Campbell Ritchie
Sheriff

Joined: Oct 13, 2005
Posts: 40052
    
  28
I have told you already why you don’t have protected members in interfaces.
jayaprakash kaluva
Greenhorn

Joined: Aug 01, 2012
Posts: 4
i did not understand what you explained regarding "why cant we have protected fields in interface ".If possibe can you please explain more eloberately .
jayaprakash kaluva
Greenhorn

Joined: Aug 01, 2012
Posts: 4
Thank a lot for your quick reply
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: How Interface is different from Abstract Class incase of Inheritence