Нужен совет

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 grandmotherName = reader.readLine(); Cat catGrandmother = new Cat(grandmotherName,null,null); String grandfatherName = reader.readLine(); Cat catGrandfather = new Cat(grandfatherName,null,null); String motherName = reader.readLine(); Cat catMother = new Cat(motherName,catGrandmother,null); String fatherName = reader.readLine(); Cat catFather = new Cat(fatherName,null,catGrandfather); 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 parent; Cat(String name) { this.name = name; } Cat(String name, Cat parent) { this.name = name; this.parent = parent; } Cat(String name, Cat mother, Cat father) { this.name = name; this.mother = mother; this.father = father; } @Override public String toString() { if (parent == null) return "The cat's name is " + name + ", no mother "; else if (parent != null) return "The cat's name is " + name + ", mother is " + parent.name; else if (mother == null) return "The cat's name is " + name + ", no mother "; else if (mother != null) return "The cat's name is " + name + ", mother is " + mother.name; else if (father == null) return "The cat's name is " + name + ", no father "; else return "The cat's name is " + name + ", father is " + father.name; } } }