why interface variables are static and final. what is reason to declare them as like that?

[ranjithkumar.gendhe kumar]

why interface variables are static and final. what is reason to declare them as like that?

[Wouter Oet]

They are implicitly static and final because instance variables don't work with polymorphism. They can be used to allow implementing classes to have access to the same set of constants.

[Muhammad Khojaye]

http://www.coderanch.com/t/178630/java-SCJA/certification/Instance-variables-interface

[Arun Giridharan]

Interface came into picture to solve the problem of Diamond shape problem.If you know what is static and final keywords that's you have the answer.

[ranjithkumar.gendhe kumar]

how interface solve the diamond shape problem

i declared like this

interface i1{
int a=12;
}
interface i2{
int a=21;
}
class exampleInterface implements i1,i2{
public static void main(String...a){
System.out.println(a);// it is compilation error
}
}


please clarify this one

[Wouter Oet]

Arun Giridharan wrote:Interface came into picture to solve the problem of Diamond shape problem.If you know what is static and final keywords that's you have the answer.

Interface where introduced to allow programming to an interface and not an implementation. This allows you to decouple the implementation and the interface.

And kumar please UseCodeTags.

[ranjithkumar.gendhe kumar]

thank you.


interface can contain class.

in which cases this will be useful explain with an example.

[Arun Giridharan]

ranjithkumar.gendhe kumar wrote:how interface solve the diamond shape problem

i declared like this

    
interface i1{
  int a;
}
interface i2{
  int a;
}
class exampleInterface implements i1,i2{
   public static void main(String...a){
            System.out.println(a);// it is compilation error
   }
}

please clarify this one

First it's not a instance variable,so please give a value.

see the following code

  
interface i1{
int a=1;
}
interface i2{
int a=2;
}
class exampleInterface implements i1,i2{
public static void main(String...a){
System.out.println(i2.a);
}
}
  

[ranjithkumar.gendhe kumar]

ok i gave values to it.

[Campbell Ritchie]

Careful about spellings: what does "k" mean? I it "OK" spelt incorrectly?

[ranjithkumar.gendhe kumar]

ok. i corrected.