// hier stand bis eben Schwachsinn
final OutputStream fileOut = new FileOutputStream("Filename");
final Writer writer = new BufferedWriter(new OutputStreamWriter(fileOut, "UTF8")));
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(eingangsDatei), "Cp1250"));
(...)
PrintWriter pw = new PrintWriter(ausgangsDatei, "UTF8");
pw.write(ausgabe);