How Interface is different from Abstract Class incase of Inheritence

[jayaprakash kaluva]

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]

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:-

public class Foo
{
   private int i;
   public Foo(int i)
   {
      this.i = i;
   }
// . . .
// public final void setI() method as usual, if required.

   public final int getI() // Cannot be changed in subclasses
   {
      return i;
   }
// ...
}

public class Bar extends Foo
{
   private int j;

   public Bar(int i, int j)
   {
      super(i);
      this.j = j;
   }
// ...
   public int getProduct()
   {
      return j * getI();
   }
}

By using the superclass field and its public method you get any access to i that you need.

[Campbell Ritchie]

I have told you already why you don’t have protected members in interfaces.

[jayaprakash kaluva]

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]

Thank a lot for your quick reply