Добрый день.
Сложно мне даются пока классы. Подскажите, почему
java.lang.NullPointerException
at com.javarush.task.task08.task0824.Solution$Human.toString(Solution.java:73)
Дети вообще не создаются, пробовал отладчиком.
package com.javarush.task.task08.task0824;
/*
Собираем семейство
*/
import java.util.ArrayList;
public class Solution {
public static void main(String[] args) {
ArrayList<Human> chidrens = new ArrayList<>();
Human Children1 = new Human("Петр",true,15);
Human Children2 = new Human("Ира",false,15);
Human Children3 = new Human("Иннокентий",true,15);
Human father = new Human("Отец Петя", true, 45, chidrens);
Human mother = new Human("Мама Даша", false, 45, chidrens);
ArrayList<Human> grandpa1 = new ArrayList<>();
ArrayList<Human> grandma1 = new ArrayList<>();
ArrayList<Human> grandpa2 = new ArrayList<>();
ArrayList<Human> grandma2 = new ArrayList<>();
grandpa1.add(father);
grandma1.add(father);
grandpa2.add(mother);
grandma2.add(mother);
Human GrandPa1 = new Human("Дедушка Ваня", true,90, grandpa1);
Human GrandMa1 = new Human("Бабушка Даша",false,85,grandma1);
Human GrandPa2 = new Human("Просто Дед", true,90, grandpa2);
Human GrandMa2 = new Human("Баба Ира",false,85,grandma2);
chidrens.add(Children1);
chidrens.add(Children2);
chidrens.add(Children3);
System.out.println(GrandPa1.toString());
System.out.println(GrandPa2.toString());
System.out.println(GrandMa1.toString());
System.out.println(GrandMa2.toString());
System.out.println(father.toString());
System.out.println(mother.toString());
System.out.println(Children1);
System.out.println(Children2);
System.out.println(Children3);
}
public static class Human {
String name;
boolean sex;
int age;
ArrayList<Human> children;
public Human(String name,boolean sex, int age)
{
this.name = name;
this.sex = sex;
this.age = age;
//this.children = children;
}
public Human(String name,boolean sex, int age, ArrayList<Human> children)
{
this.name = name;
this.sex = sex;
this.age = age;
this.children = children;
}
public String toString() {
String text = "";
text += "Имя: " + this.name;
text += ", пол: " + (this.sex ? "мужской" : "женский");
text += ", возраст: " + this.age;
int childCount = this.children.size();
if (childCount > 0) {
text += ", дети: " + this.children.get(0).name;
for (int i = 1; i < childCount; i++) {
Human child = this.children.get(i);
text += ", " + child.name;
}
}
return text;
}
}
}