I can't see the mistake,please help.
package com.codegym.task.task06.task0621;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
/*
Cat relations
*/
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); // 1
String grandMotherName = reader.readLine();
Cat catGrandMother = new Cat(grandMotherName); // 2
String fatherName = reader.readLine();
Cat catFather = new Cat(fatherName, catGrandFather);
String motherName = reader.readLine();
Cat catMother = new Cat(motherName, catGrandMother);
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, father;
Cat(String name) {
this.name = name;
}
Cat (String name,Cat mother){
this.name = name;
this.mother = mother;
}
Cat (String name,Cat mother, Cat father){
this.name = name;
this.mother = mother;
this.father = father;
}
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.name+" is the father";
}
else if (father == null){
return "The cat's name is " + name + ", " + mother.name + " is the mother, no father ";
}
else if (mother == null && father == null){
return "The cat's name is " + name + ", no mother, no father ";
}
else {
return "The cat's name is " + name + ", " + mother.name + " is the mother, " + father.name + " is the father ";
}
}
}
}