Помогите в чем ошибка!!!!! как угодить валидатору, вроде все работает! Что ему нужно!?????
package com.javarush.task.task18.task1825;
/*
Собираем файл
*/
import java.io.*;
import java.util.TreeSet;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
TreeSet<String> listFilePart = new TreeSet<>();
String collectionFileName = null;
String filePart = reader.readLine();
while (!filePart.equals("end")) {
listFilePart.add(filePart);
filePart = reader.readLine();
}
reader.close();
String[] result = listFilePart.first().split("\\.");
for (int i = 0; i < result.length - 2; i++) {
if (collectionFileName == null) collectionFileName = (result[i] + ".");
else collectionFileName += (result[i] + ".");
}
collectionFileName = collectionFileName + "." + result[result.length - 1];
FileOutputStream fileOutputStream = new FileOutputStream(collectionFileName);
for (String s : listFilePart) {
FileInputStream fileInputStream = new FileInputStream(s);
byte[] buff = new byte[1000];
while (fileInputStream.available() > 0) {
int count = fileInputStream.read(buff);
fileOutputStream.write(buff, 0, count);
}
fileInputStream.close();
}
fileOutputStream.close();
}
}