почему так выводит?
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 grenfatherName = reader.readLine();
Cat catGrenfather = new Cat(grenfatherName,null, null);
String grenmatherName = reader.readLine();
Cat catGrenmather = new Cat(grenmatherName, null, null);
String fatherName = reader.readLine();
Cat catFather = new Cat(fatherName, null, catGrenfather);
String motherName = reader.readLine();
Cat catMother = new Cat(motherName, catGrenmather, null);
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(catGrenfather);
System.out.println(catGrenmather);
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 parentMother;
private Cat parentFather;
Cat(String name) {
this.name = name;
}
Cat(String name, Cat parentMother, Cat parentFather) {
this.name = name;
this.parentMother = parentMother;
this.parentFather = parentFather;
}
@Override
public String toString() {
if (parentMother == null && parentFather == null)
return "The cat's name is " + name + ", no mother, " + "no father";
if(parentFather == null)
return "The cat's name is " + name + ", mother is "+ parentMother + ", no father";
if (parentMother == null)
return "The cat's name is " + name + ", mother is " + ", father is " + parentFather;
else
return "The cat's name is " + name + ", mother is "+ parentMother + ", father is " + parentFather;
}
}
}