Спасибо!
package com.javarush.task.task18.task1809;
/*
Реверс файла
*/
import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
public class Solution {
public static void main(String[] args) throws IOException{
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
String fileName1 = bufferedReader.readLine();
String fileName2 = bufferedReader.readLine();
bufferedReader.close();
FileInputStream inputStream = new FileInputStream(fileName1);
FileOutputStream outputStream = new FileOutputStream(fileName2);
byte[] buffer = new byte[inputStream.available()];
for(int j = buffer.length - 1; j >= 0; j--){
outputStream.write(buffer[j]);
}
inputStream.close();
outputStream.close();
}
}