Что-то не вкурю уже

package com.javarush.task.task06.task0621; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* Родственные связи кошек */ public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String grandFatherName = reader.readLine(); Cat catGrandFather = new Cat(grandFatherName); String grandMotherName = reader.readLine(); Cat catGrandMother = new Cat(grandMotherName); String fatherName = reader.readLine(); Cat catFather = new Cat(fatherName); String motherName = reader.readLine(); Cat catMother = new Cat(motherName); String sonName = reader.readLine(); Cat catSon = new Cat(sonName, catMother, catFather); String daughterName = reader.readLine(); Cat catDaughter = new Cat(daughterName, catMother, catFather); System.out.println(catGrandFather); System.out.println(catGrandMother); System.out.println(catFather); System.out.println(catMother); System.out.println(catSon); System.out.println(catDaughter); } public static class Cat { private String name; private Cat mother; private Cat father; private Cat grandMother; private Cat grandFather; Cat(String name) { this.name = name; } Cat(String name, Cat mother, Cat father) { this.name = name; this.mother = mother; this.father = father; } Cat(String name, Cat mother, Cat father, Cat grandMother, Cat grandFather) { this.name = name; this.mother = mother; this.father = father; this.grandMother = grandMother; this.grandFather = grandFather; } @Override public String toString() { if (mother == null && father == null) return "The cat's name is " + name + ", no mother, no father" ; else if (mother == null) return "The cat's name is " + name + ", no mother, father is " + grandFather.name; else if (father == null) return "The cat's name is " + name + ", mother is " + grandMother.name + ", no father"; else return "The cat's name is " + name + ", mother is " + mother.name + ", father is " + father.name; /* The cat's name is дедушка Вася, no mother, no father The cat's name is бабушка Мурка, no mother, no father The cat's name is папа Котофей, no mother, father is дедушка Вася The cat's name is мама Василиса, mother is бабушка Мурка, no father The cat's name is сын Мурчик, mother is мама Василиса, father is папа Котофей The cat's name is дочь Пушинка, mother is мама Василиса, father is папа Котофей */ /* if (parent == null) return "The cat's name is " + name + ", no mother "; else return "The cat's name is " + name + ", mother is " + parent.name;*/ } } }