Все работает, все потоки закрыты, че он хочет?
package com.javarush.task.task18.task1809;
/*
Реверс файла
*/
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.util.Collections;
import java.util.Scanner;
public class Solution {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(System.in);
FileInputStream fileInputStream = new FileInputStream(scanner.nextLine());
FileOutputStream outputStream = new FileOutputStream(scanner.nextLine());
scanner.close();
byte[] buffer = new byte[fileInputStream.available()];
fileInputStream.read(buffer, 0, fileInputStream.available());
int n = buffer.length;
byte temp;
for (int i = 0; i < n/2; i++) {
temp = buffer[n-i-1];
buffer[n-i-1] = buffer[i];
buffer[i] = temp;
}
System.out.println(buffer[0] + buffer[buffer.length-1]);
outputStream.write(buffer, 0, buffer.length);
fileInputStream.close();
outputStream.close();
}
}