父类构造函数调用被子类重写的方法——要避免！

class Base {//定义了一个名为i的实例变量//private int i = 2;public Base() {this.display();}public void display() {System.out.println("Base::display()"+i);}}//继承Base的Derived子类class Derived extends Base {//定义了一个名为i的实例变量//private int i = 22;//构造器，将实例变量i初始化为222public Derived() {i = 222;}public void display() {System.out.println("Derived::display()"+i);}}public class Test {public static void main(String[] args) {//创建Derived的构造器创建实例new Derived();}}/*Derived::display()0请按任意键继续. . .*/