Даже посмотрел у человека, у которого все ок- этот кусок такой же
package com.javarush.task.task31.task3101;
import java.io.*;
import java.util.*;
/*
Проход по дереву файлов
*/
public class Solution {
public static void main(String[] args) throws IOException {
FileInputStream inputStream;
File first=new File(args[0]);
File second=new File(args[1]);
File destination=new File(second.getParent()+"/allFilesContent.txt");
FileUtils.renameFile(second,destination);
Queue<File> queue=new PriorityQueue<>();
Map<String,String> map=new TreeMap<>();
Collections.addAll(queue,first.listFiles());
while (!queue.isEmpty()){
File current=queue.remove();
if (current.isDirectory()){
for (File x:current.listFiles()) {
queue.add(x);
}
}else if (current.length()<=50){
map.put(current.getName(),current.getAbsolutePath());
}
}
FileOutputStream fileOutputStream = new FileOutputStream(destination, true);
for (Map.Entry<String, String> value : map.entrySet()){
inputStream = new FileInputStream(value.getValue());
byte[] buff = new byte[inputStream.available()];
fileOutputStream.write(buff);
fileOutputStream.write("\n".getBytes());
inputStream.close();
}
fileOutputStream.close();
}
}