Валидатор пишет, что неверно заносятся данные в result. Подскажите пожалуйста, почему.
package com.javarush.task.task22.task2207;
import java.util.*;
import java.io.*;
/*
Обращенные слова
*/
public class Solution {
public static List<Pair> result = new LinkedList<>();
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String fileName = reader.readLine();
reader.close();
//C:\Java\file.txt
BufferedReader input = new BufferedReader(new FileReader(fileName));
StringBuilder builder = new StringBuilder(input.readLine());
String s = builder.toString();
input.close();
String[] str = s.split(" ");
//Промежуточный результат
ArrayList<String> list = new ArrayList<>();
Collections.addAll(list, str);
for (int i = 0; i < list.size(); i++) {
for (int j = 0; j < list.size(); j++) {
StringBuilder rev = new StringBuilder(list.get(j));
rev.reverse();
String a = rev.toString();
if (list.get(i).equals(a)) {
Pair pair = new Pair(list.get(i), list.get(j));
if (!result.contains(pair)) {
result.add(pair);
}
list.set(i, "checked");
//list.set(j, "checked");
}
}
}
//System.out.println(result);
}
public static class Pair {
String first;
String second;
public Pair() {
}
public Pair(String first, String second) {
this.first = first;
this.second = second;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Pair pair = (Pair) o;
if (first != null ? !first.equals(pair.first) : pair.first != null) return false;
return second != null ? second.equals(pair.second) : pair.second == null;
}
@Override
public int hashCode() {
int result = first != null ? first.hashCode() : 0;
result = 31 * result + (second != null ? second.hashCode() : 0);
return result;
}
@Override
public String toString() {
return first == null && second == null ? "" :
first == null ? second :
second == null ? first :
first.compareTo(second) < 0 ? first + " " + second : second + " " + first;
}
}
}