My solution works. Help please.
package de.codegym.task.task18.task1820;
/*
Zahlen runden
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
// C:\Users\vince\Desktop\Test1.txt
String file1 = reader.readLine();
String file2 = reader.readLine();
StringBuilder zahlen = new StringBuilder();
FileInputStream inputStream = new FileInputStream(file1);
FileOutputStream outputStream = new FileOutputStream(file2);
if (inputStream.available() > 0){
byte[] buffer1 = new byte[inputStream.available()];
byte[] buffer2;
int count = inputStream.read(buffer1);
int length = buffer1.length;
for (int i=0; i<length; i++){
byte b = buffer1[i];
char c = (char) b;
//String s = Byte.toString(b);
zahlen.append(c);
}
String[] parts = String.valueOf(zahlen).split(" ");
// StringBuilder "zahlen" löschen
zahlen = new StringBuilder();
// in int-Zahlen umwandeln und als String wieder in parts speichern
for (int i=0; i< parts.length; i++){
double d = Double.parseDouble(parts[i]);
int ganzeZahl = (int) d;
parts[i] = String.valueOf(ganzeZahl);
zahlen.append(parts[i]).append(" ");
}
buffer2 = new byte[zahlen.length()];
for (int i=0; i<zahlen.length(); i++){
char c = zahlen.charAt(i);
byte b = (byte) c;
buffer2[i] = b;
}
// Schreiben in file2
outputStream.write(buffer2, 0, buffer2.length);
}
inputStream.close();
outputStream.close();
}
}