public class Runen {

@SneakyThrows
public static void main(String[] args) {

Properties properties = new Properties();
BufferedInputStream stream = new BufferedInputStream(new FileInputStream("src/main/java/runen.properties"));
properties.load(stream);
stream.close();

String user = "Prophets";

List<String> runenList = new ArrayList<>(properties.stringPropertyNames());

boolean entschieden = false;

while (!entschieden) {
int randomNum = new Random().nextInt(runenList.size());

String rune = runenList.get(randomNum);

if (properties.getProperty(rune).isEmpty()) {
entschieden = true;
properties.setProperty(rune, user);
System.out.println("Wir geben dem user " + user + " die [B]" + rune + "[/B]");
} else {
System.out.println("nochmal wuerfeln...");
}
}


try (OutputStream output = new FileOutputStream("src/main/java/runen.properties")) {

properties.store(output, null);

} catch (IOException io) {
io.printStackTrace();
}
}
}