1、在new B一个实例时首先要进行类的装载。(类只有在使用New调用创建的时候才会被java类装载器装入) 2、在装载类时,先装载父类A,再装载子类B 3、装载父类A后,完成静态动作(包括静态代码和变量,它们的级别是相同的,安装代码中出现的顺序初始化) 4、装载子类B后,完成静态动作
类装载完成,开始进行实例化 1、在实例化子类B时,先要实例化父类A 2、实例化父类A时,先成员实例化(非静态代码) 3、父类A的构造方法 4、子类B的成员实例化(非静态代码) 5、子类B的构造方法 先初始化父类的静态代码--->初始化子类的静态代码-->初始化父类的非静态代码--->初始化父类构造函数--->初始化子类非静态代码--->初始化子类构造函数
- abstract class base
- {
- public int age=getNumber(100);
- static{
- System.out.println("base static block");
- }
- {
- System.out.println("base nonstatic block");
- }
- static int sage=getNumber(50);
- base(){
- System.out.println(age);
- System.out.println("base start");
- draw();//会调用子类覆盖后的方法,这儿是0!
- System.out.println("base end");
- }
- static int getNumber(int base){
- System.out.println("base.getNumber int" base);
- return base;
- }
- public void draw(){
- System.out.println("base.draw");
- }
- }
- public class initializeOrder extends base{
- public int age=getNumber(1001);
- private int _radius=getNumber(10);
- static int sage=getNumber(250);
- static{
- System.out.println("subclass static block");
- }
- {
- System.out.println("subclass nonstatic block");
- }
- initializeOrder(int radius){
- _radius=radius;
- System.out.println(age);
- draw();//这儿是1000
- System.out.println("initializeOrder initialized");
- }
- public void draw(){
- System.out.println("initializeOrder.draw " _radius);
- }
- public static void main(String[] args) { // TODO Auto-generated method stub
- new initializeOrder(1000);
- }
- }
- 输出为:
- base static block
- base.getNumber int50
- base.getNumber int250
- subclass static block
- base.getNumber int100
- base nonstatic block
- 100
- base start
- initializeOrder.draw 0
- base end
- base.getNumber int1001
- base.getNumber int10
- subclass nonstatic block
- 1001
- initializeOrder.draw 1000
- initializeOrder initialized