Not all file input streams were closed??

Question about the task

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Hi everyone, Apparently there is a stream that needs to be closed. It might be that I'm going blind or something but I can only see three streams in my code. Hope you can see the missing stream that is not being closed : | Thanks in advance!

Let's build a file from various pieces.
Read file names from the console.
Each file has a name: <someName>.partN.

For example, Lion.avi.part1, Lion.avi.part2, ..., Lion.avi.part37.

The file names are supplied in random order. The word "end" is used to stop reading in file names.
In the folder where all the files are located, create a file without the "part" suffix, i.e. without ".<partN>".

For example, Lion.avi.

Use a buffer to copy all the bytes from the partial files to the created file.
Copy the first in the proper order, first the first part, then the second, ..., finally - the last part.
Close the streams.

Requirements:

The program must read file names from the console until the word "end" is entered.
Create a stream to write to the file without the "part" suffix (".<partN>") in the folder with all the "part" files.
Copy all the bytes from the *.partN files to the new file.
You should use a buffer for the reading and writing.
The file streams must be closed.
Don't use static variables.

package com.codegym.task.task18.task1825; import java.io.*; import java.util.*; /* Building a file */ public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String fileName; TreeSet<String> filesNames = new TreeSet<>(); while (!(fileName = reader.readLine()).equals("end")) filesNames.add(fileName); String outputFileName = ""; String[] words = filesNames.first().split("\\."); for (int i = 0; i < words.length; i++) { if (i == words.length - 2) { outputFileName += words[i]; break; } outputFileName += words[i] + "."; } BufferedWriter fileWriter = new BufferedWriter(new FileWriter(outputFileName, true)); BufferedReader fileReader = null; for (String s : filesNames) { fileReader = new BufferedReader(new FileReader(s)); String line; while ((line = fileReader.readLine()) != null) fileWriter.write(line); } reader.close(); fileWriter.close(); fileReader.close(); } }

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Jesús de Llera

Level 23 , Badajoz, Spain

8 June 2019, 21:31

Ok, just moved fileReader.close() inside the for each and sorted the issue. Don't really know what was wrong with the previous solution... Validator is really picky sometimes XD

Daniel Walbolt

Level 22 , Waterville, United States

26 July 2020, 13:10

Well to anyone else who finds this, the problem is that there were multiple different "fileReaders" and "fileWriters" variables that are initialized and then used, but never closed/discarded. You closed the variable but not the instance of "BufferedReader(new FileReader() )" that was created within each iteration of the for loop. CodeGym is just trying to teach you good habit, because if you constantly created input streams/output streams, it would eventually clog up memory in a real application environment. In our case, our program only runs for a short amount of time, so the memory impacts are minimal.