В чём ошибка?
package com.javarush.task.task18.task1819;
import java.util.*;
import java.lang.*;
import java.io.*;
/*
Объединение файлов
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String name1 = reader.readLine();
String name2 = reader.readLine();
FileInputStream inputStream1 = new FileInputStream(name1);
FileInputStream inputStream2 = new FileInputStream(name2);
byte[] tmp = new byte[inputStream1.available()];
inputStream1.read(tmp);
FileOutputStream outputStream = new FileOutputStream(name1, true);
while (inputStream2.available()>0){
outputStream.write(inputStream2.read());
outputStream.write(tmp);
}
inputStream1.close();
inputStream2.close();
outputStream.close();
}
}