类的执行顺序

sun201200204

package com.payton.polymorphism;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("Lettuce()");    }}class Lunch extends Meal {    private Bread b = new Bread();    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();    }}

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

调用顺序：
1、调用基类的构造函数。（先创建根，下一级派生类，....直到最后一个继承类的构造函数）
2、成员对象按照其声明顺序进行初始化。
3、执行继承类的构造函数。