java面试----题库2

题目1

class X {
    Y b = new Y();
    X() {
        System.out.print("X");
    }
}
class Y {
    Y() {
        System.out.print("Y");
    }
}

public class UserDao extends X{
        Y y = new Y();
        UserDao(){
            System.out.print("Z");
        }
        public static void main(String[] args) {
            new UserDao();
        }
}

先初始化父类数据，在初始化子类数据。结果 YXYZ

 

题目2

public class DemoTest {
    public static void main(String[] args) {
        A a = new A();
        a.b();
        a.b();
    }
}

class A{
    private int b;
    void b(){
        final int a=b;
        b = 1;
        System.out.println(a);
    }
}