public class A {    public int i = 10;    public static void test(A a) {        a.i += 10;    }    public static void main(String[] args) {        A a = new A();        test(a);        System.out.println(a.i);        A b = a;        test(b);        System.out.println(a.i);        System.out.println(b.i);        A c = a;        c.i = 0;        System.out.println(c.i);        System.out.println(b.i);        System.out.println(a.i);    }}