如何理解Java中基类子对象的构建过程从"基类向外"进行扩散的?

import static net.mindview.util.Print.*; //《java编程思想》提供的类库
/**
 * @author Administrator
 *
 */
public class Cat extends Animal {
 public Cat() {
 // TODO Auto-generated constructor stub
 print("Caretoon constructor");
 }
 public static void main(String[] args) {
 Cat x = new Cat();
 }
}
class Biology {
 Biology() {
 // TODO Auto-generated constructor stub
 print("Art constructor");
 }
}
class Animal extends Biology {
 Animal() {
 // TODO Auto-generated constructor stub
 print("Drawing constructor");
 }
}