код робит, а ошибки выскакивают, в чем дело?
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, null, null);
String grandMotherName = reader.readLine();
Cat catGrandMother = new Cat(grandMotherName, null, null);
String fatherName = reader.readLine();
Cat catFather = new Cat(fatherName, null, catGrandFather);
String motherName = reader.readLine();
Cat catMother = new Cat(motherName, catGrandMother, 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(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 parent;
private Cat grandparent;
Cat(String name, Cat parent, Cat grandparent) {
this.name = name;
this.parent = parent;
this.grandparent = grandparent;
}
@Override
public String toString() {
if (parent == null && grandparent==null)
return "The cat's name is " + name + ", no mother, no father";
else if(grandparent == null && parent !=null)
return "The cat's name is " + name + ", mother is " + parent.name;
else if(parent == null && grandparent !=null)
return "The cat's name is " + name + ", father is " + grandparent.name;
else return "The cat's name is " + name + ", mother is " + parent.name + " father is " + grandparent.name;
}
}
}