为什么这个继承父类的结果会出现NULL

1，源代码
package com.java.demo;
public class Dervied extends Base {

private String name = "dervied";

public Dervied() {
    tellName();
    printName();
}

public void tellName() {
    System.out.println("Dervied tell name: " + name);
}

public void printName() {
    System.out.println("Dervied print name: " + name);
}

public static void main(String[] args){

    new Dervied();    
}

}

class Base {

private String name = "base";

public Base() {
    tellName();
    printName();
}

public void tellName() {
    System.out.println("Base tell name: " + name);
}

public void printName() {
    System.out.println("Base print name: " + name);
}

}

,2，结果
Dervied tell name: null
Dervied print name: null
Dervied tell name: dervied
Dervied print name: dervied

先执行父类的tellName();这里会调用子类的tellName();单子类的name此时还未初始化，是null