public String CIP(String c){
    final String[] result = new String[1];
    CheckFIETask task1 = new CheckFIETask(c);
    task1.setOnSucceeded((succeededEvent) -> {
        if (task1.getValue().equals(String.valueOf(true))){
            result[0] = ("IP reachable");
        } else {
            result[0] = ("IP not reachable");
        }

        System.out.println(result[0]); //works

    });
    System.out.println(result[0]); // null

    ExecutorService executorService1 = Executors.newFixedThreadPool(1);
    executorService1.execute(task1);
    executorService1.shutdown();

    System.out.println(result[0]); // null

    return result[0]; //null
}