Interface

[Rambabu Gonela]

all variables declared in interface are by defualt public static and final ..ok but in interface why compulsary we have to assign value to variable... its already static... in class by default it will take value as 0.
but why in interface giving error(already its static variable so its should take value as 0 by default, but its not happening)

interface I
{
int i;
}

error:
C:\Rambabu>javac I.jav
I.java:3: = expected
int i;
1 error

Please .. give me explanation ok bye

[Ben Souther]

Moving to Java In General (Intermediate).

This forum is for servlet questions.

[Prem Kashyap]

It needs to be initialized because it is final. Final variables needs to be initialized either while declaring or in the constructor. Interface do not have constructors. So it has to be initialized during declration.

Ex:
int i = 10; //Will Compile

int i; // Do not Compile.

Regards
Prem

[David Nemeskey]

Final fields have to be initialized in the initializer, or in a constructor.

Static finals can only be initialized in the static initializer:

static final int i = 3;
 
static final int j;
static {
    j = 5;
}

Final fields can be initialized either in the initializer or in a contructor:

publix class FinalTest {
    final int i = 3;
 
    final int j;
    {
        j = 5;
    }
 
    final int k;
    public FinalTest() {
        k = 7;
    }
}

An interface cannot have initializers or constructors, so you can only use the first form.

[Rambabu Gonela]

thank you prem and david