Не понимаю в чем тут именно ошибка.
package com.javarush.task.task18.task1808;
import java.io.*;
/*
Разделение файла
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
String inputFile = bf.readLine();
String outputFile1 = bf.readLine();
String outputFile2 = bf.readLine();
try(FileInputStream fi = new FileInputStream(inputFile);
FileOutputStream fo = new FileOutputStream(outputFile1);
FileOutputStream fr = new FileOutputStream(outputFile2);){
long fielsize = new File(inputFile).length();
int bf1 = (int) (fielsize/2 + (fielsize % 2));
int bf2 = (int) (fielsize/2 );
byte[] buffer1 = new byte[bf1];
fi.read(buffer1);
fo.write(buffer1);
byte[] buffer2 = new byte[bf2];
fi.read(buffer2);
fr.write(buffer2);
}
}
}