может я чего то не замечаю
package com.javarush.task.task18.task1825;
import java.io.*;
import java.util.*;
/*
Собираем файл
*/
public class Solution {
public static void main(String[] args) {
Map<Integer, String> map = new TreeMap<>();
try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) {
String fileName = null;
while (!(fileName = reader.readLine()).equals("end")) {
int num = Integer.parseInt(fileName.substring(fileName.lastIndexOf("t") + 1));
map.put(num, fileName);
}
if (map.isEmpty()) {
System.exit(0);
}
for (Map.Entry<Integer, String> entry : map.entrySet()) {
try (InputStream inputStream = new BufferedInputStream(new FileInputStream(entry.getValue()));
OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(map.get(0).substring(0, map.get(0).lastIndexOf("."))))) {
byte[] buffer = new byte[inputStream.available()];
if (inputStream.available() > 0) {
inputStream.read(buffer);
outputStream.write(buffer);
}
} catch (IOException e) {
e.printStackTrace();
}
}
} catch (IOException e) {
}
}
}