JAVA初始化顺序略谈

package com.wensefu.constructor;
class Meal{
Meal(){
System.out.println("Meal()");
}
}
class Bread{
Bread(){
System.out.println("bread()");
}
}
class Chesse{
Chesse(){
System.out.println("Chesse()");
}
}
class Lettuce{
Lettuce(){
System.out.println("Lettuce()");
}
}
class Lunch extends Meal{
Lunch(){
System.out.println("Lunch()");
}
}
class PortableLunch extends Lunch{
PortableLunch(){
System.out.println("PortableLunch()");
}
}
/*
* 1,调用基类构造器，此过程会反复递归下去
* 2，按照声明顺序调用成员的初始化方法
* 3，调用导出类构造器的主体
*/
public class Demo extends PortableLunch{

private Bread b=new Bread();
private Chesse c=new Chesse();
private Lettuce l=new Lettuce();

public Demo() {
// TODO Auto-generated constructor stub
System.out.println("Demo()");
}
public static void main(String[] args) {
new Demo();
}

}

输出：
Meal()
Lunch()
PortableLunch()
bread()
Chesse()
Lettuce()
Demo()
package com.wensefu.duotai;
abstract class Glyph{
abstract void draw();
Glyph(){
System.out.println("Glyph() before draw()");
draw();
System.out.println("Glyph() after draw()");
}
}
class RoundGlyph extends Glyph{
private int radius=1;
RoundGlyph(int r){
radius=r;
System.out.println("RoundGlyph.RoundGlyph(), radius="+radius);
}
@Override
void draw() {
// TODO Auto-generated method stub
System.out.println("RoundGlyph.draw(),radius="+radius);
}
}
/*
* 初始化实际过程：
* 1，在其他任何事物发生之前，将分配给对象存储空间初始化成二进制的零
* 2，调用基类构造器，此时，调用被覆盖后的draw()方法，（在调用RoundGlyph构造器之前调用），
* 3，按照声明的顺序调用成员的初始化方法
* 4，调用导出类的构造方法
*/
public class PolyConstructors {

public static void main(String[] args) {
new RoundGlyph(6);
}
}

输出：
Glyph() bef