Can you check why validation id not ok?
package pl.codegym.task.task18.task1819;
/*
Łączenie plików
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String file1 = reader.readLine();
String file2 = reader.readLine();
FileInputStream inputStream1 = new FileInputStream(file1);
FileInputStream inputStream2 = new FileInputStream(file2);
FileOutputStream outputStream1 = new FileOutputStream(file1, false);
FileOutputStream outputStreamAppend = new FileOutputStream(file2, true);
while (inputStream1.available() > 0) {
int data1 = inputStream1.read(); //odczytaj pierwszy plik
outputStreamAppend.write(data1); //zapisz pierwszy plik za drugim
}
while (inputStream2.available() > 0) {
int data2 = inputStream2.read();
outputStream1.write(data2);
}
reader.close();
inputStream1.close();
inputStream2.close();
outputStream1.close();
outputStreamAppend.close();
}
}