java中继承与初始化顺序 2

本代码拷贝自《Java编程思想第四版》多态章节。

class Meal{
    Meal() { System.out.println("Meal()");}
}

class Bread{
    Bread() { System.out.println("Bread()");}
}
class Cheese{
    Cheese() { System.out.println("Cheese()");}
}
class Lettuce{
    Lettuce() { System.out.println("Luttuce()");}
}
class Lunch extends Meal{
    Lunch() { System.out.println("Lunch()");}
}
class PortableLunch extends Lunch{
    PortableLunch() { System.out.println("PortableLunch()");}
}

public class Sandwich extends PortableLunch{
    private Bread b = new Bread();
    private Cheese c = new Cheese();
    private Lettuce l = new Lettuce();
    public Sandwich() { System.out.println("Sandwich()"); }
    public static void main(String[] args) {
        new Sandwich();
    }
}

输出结果：

Meal()
Lunch()
PortableLunch()
Bread()
Cheese()
Luttuce()
Sandwich()

可以看出对象调用构造器的顺序：调用基类构造器->按声明顺序调用成员的初始方法 ->调用构造器主体