For a variable used in a function that is called very often and for implementation in J2ME on a blackberry (if that changed something, can you explain)?

class X {
    int i;
    public void someFunc(int j) {
        i = 0;
        while( i < j ){
            [...]
            i++;
        }
    }
}

or

class X {
    static int i;
    public void someFunc(int j) {
        i = 0;
        while( i < j ){
            [...]
            i++;
        }
    }
}

or

class X {
    public void someFunc(int j) {
        int i = 0;
        while( i < j ){
            [...]
            i++;
        }
    }
}

I know there is a difference how a static versus non-static class variable is accessed, but I don't know it would affect the speed. I also remember reading somewhere that in-function variables may be accessed faster, but I don't know why and where I read that.

Background on the question: some painting function in games are called excessively often and even small difference in access time can affect the overall performance when a variable is used in a largish loop.