java没有指针操作，不能通过调用函数改变整数的值，请问调用函数改变整数？？

i的值没有改变，请问如何让其改变？？？

没办法，只能用一个类包裹下

class Untitled {
    public static void add(Warpper w)
    {
        w.i++;
    }
    public static void main(String[] args) {
        Warpper w = new Warpper();
        w.i = 1;
        add(w);
        System.out.println(w.i);
    }
}

class Warpper
{
    public int i;
}

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int i = scanner.nextInt();
         i = add(i);
        System.err.println(i);
    }

    public   static Integer add(int i) {
         return  i+1;
    }

    static int i = 0;
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        i = scanner.nextInt();
        add();
        System.err.println(i);
    }

    public   static void add() {
         i =  i+1;
    }