JAVA-笔试-关于继承中构造器调用问题

/**
 * 判断运行结果
 */
public class supertest {
    public static void main(String[] args) {
        new A(new B());
    }
}

class A{
    public A(){
        System.out.println("A");
    }

    public A(B b){
        this();
        System.out.println("AB");
    }
}

class B{
    public B(){
        System.out.println("B");
    }
}

答案为：

        B
        A
        AB

---

/**
 * 判断运行结果
 */
public class supertest {
    public static void main(String[] args) {
        new A(new B());
    }
}

class A{
    public A(){
        System.out.println("A");
    }

    public A(B b){
        this();
        System.out.println("AB");
    }
}

class B extends A{
    public B(){
        System.out.println("B");
    }
}

答案为：

        A
        B
        A
        AB

---

/**
 * 判断运行结果
 */
public class supertest {
    public static void main(String[] args) {
        Father f = new Father();
        Son s = new Son();
        System.out.println(f.getInfo());
        System.out.println(s.getInfo());
        s.test();
        System.out.println("-----------------"); 
        s.setInfo("大儿子");
        System.out.println(f.getInfo());
        System.out.println(s.getInfo());
        s.test();
    }
}

class Father{
    private String info = "father";

    public String getInfo() {
        return info;
    }

    public void setInfo(String info) {
        this.info = info;
    }
}

class Son extends Father{
    private String info = "儿子";
    public void test(){
        System.out.println(this.getInfo());
        System.out.println(super.getInfo());
    }
}

答案为：

        father
        father
        father
        father
        -----------------
        father
        大儿子
        大儿子
        大儿子