Тестовая задача проходит, что хочет валидатор
package com.javarush.task.task22.task2207;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
/*
Обращенные слова
*/
public class Solution {
public static List<Pair> result = new LinkedList<>();
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String fileName = reader.readLine();
reader.close();
BufferedReader br = new BufferedReader(new FileReader(args[0]+fileName));
ArrayList<String> wordsList = new ArrayList<String>();
String str;
while ((str = br.readLine()) != null) {
for (String word : str.split("\\s+")) {
if (!word.isEmpty())
wordsList.add(word);
}
}
for (int i=0; i<wordsList.size(); i++){
String s1 = wordsList.get(i);
String s2;
StringBuilder sb = new StringBuilder(s1).reverse();
s2=sb.toString();
for (int j=i+1; j<wordsList.size(); j++){
if (s2.equals(wordsList.get(j))){
Pair pair = new Pair();
pair.first = s1;
pair.second = s2;
if (result.isEmpty()){
result.add(pair);
}else {
int count=0;
for (int k=0; k<result.size(); k++){
if (pair.equals(result.get(k))){
count++;
}
}
if (count==0) result.add(pair);
}
}
}
}
for (int i=0; i<result.size(); i++){
System.out.println(result.get(i).toString());
}
}
public static class Pair {
String first;
String second;
protected Pair() {
}
@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;
}
}
}
Очень удобно