参考：On Java 8
- 基类构造器被调用。这个步骤重复递归，直到根基类的构造器被调用，然后是它的派生类，以此类推，直到最底层的派生类构造器被调用。
- 按声明顺序初始化成员。
- 最终调用派生类的构造器。
例子：
// polymorphism/Sandwich.java
// Order of constructor calls
// {java polymorphism.Sandwich}
package 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 {
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:
Meal()
Lunch()
PortableLunch()
Bread()
Cheese()
Lettuce()
Sandwich()
