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JavaFX how to change scene within a runnable

I'm having an app which enables a customer to place an order for a ride (as in Uber), initially considered in a "WAITING" phase. When a driver accepts the order, it is automatically set in an "ACCEPTED" phase.
When ACCEPTED, the user is going to be redirected to another scene, telling him that he needs to wait for his rider to pick him up.
I decided to create a thread that checks every 250ms if the status of his order was set to ACCEPTED, like that:
public class AcceptanceRunnable implements Runnable {
private boolean running;
public AcceptanceRunnable() {
running = true;
}
public void run() {
do {
try {
Thread.sleep(250);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (OrderService.checkIfAccepted(OrderSession.getOrder())) {
// move to other scene
break;
}
} while(running);
}
public void setRunning(boolean running) {
this.running = running;
}
}
This AcceptanceRunnable class gets instantiated within the controller in the initialize() method:
#FXML
public void initialize() throws InterruptedException, IOException {
sourceAddress.setText("From: " + OrderSession.getOrder().getSourceAddress());
destinationAddress.setText("To: " + OrderSession.getOrder().getDestinationAddress());
price.setText("You'll need to pay RON " +
UserService.calculatePrice(UserSession.getUser()) + " for this ride.");
acceptanceRunnable = new AcceptanceRunnable();
Thread t = new Thread(acceptanceRunnable);
t.start();
}
Everything works fine. If I just print out some lines while waiting for the order's status to get changed, it seems to be okay. The problem is, I want my user to be redirected to another scene, if his order gets accepted.
This means, I need to insert something in place of the comment made in my AcceptanceRunnable.run() method.
I also tried changing the scene by having a method called ifAccepted() inside my controller, which actually triggers the method that changes the scene:
if (OrderService.checkIfAccepted(OrderSession.getOrder())) {
try {
Class<?> controller = Class.forName("com.example.yuber.controllers.CustomerWaitController");
Method ifAccepted = controller.getMethod("ifAccepted");
ifAccepted.invoke(controller.newInstance());
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
}
break;
}
But I only get some NullPointerException and I'm pretty sure that what I do here isn't really correct.
Any opinions?

As Slaw suggested, using Platform#runLater(Runnable) fixed my problem.
What I actually did was add my run() method from the Runnable inside my controller, renaming it to handleTread():
public void handleThread() {
do {
try {
Thread.sleep(250);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (OrderService.checkIfAccepted(OrderSession.getOrder())) {
Platform.runLater(() -> {
try {
SceneService.NewScene("/com/example/yuber/accepted-view.fxml", (Stage) rootPane.getScene().getWindow(), rootPane.getScene());
} catch (IOException e) {
e.printStackTrace();
}
});
break;
}
} while(running);
}
Not using Platform.runLater(...) would result in receiving a Not on FX Application Thread error.
Everything seems to be fine now.

ListenableFuture - how to wait before return

I have a Spring Cloud microservice that posts message on a Kafka broker, this microservice is accessible thru a REST api.
I want to return the submit status back to the caller but seems like Java does not await. How to make this to wait either success or failure before my code returns?
Heres the code:
kafkaProduc.send("topictest", msg).addCallback(
new ListenableFutureCallback<SendResult<String, ExecutionDataMessage>>() {
#Override
public void onSuccess(SendResult<String, ExecutionDataMessage> result) {
eresp.status = "ok";
eresp.msg = "message submitted successfully";
}
#Override
public void onFailure(Throwable ex) {
eresp.status = "error";
eresp.msg = "failure while sending data to kafka. exception: " + ex.getMessage();
}
});
HttpStatus erespStatus = eresp.status == "ok" ? HttpStatus.CREATED : HttpStatus.BAD_REQUEST;
return new ResponseEntity<ExecutionResponse>(eresp, erespStatus);

The callback is for when you want an asynchronous result. If you want to block the calling thread, use future.get()...
ListenableFuture<SendResult<String, String>> future = template.send("foo", "bar");
try {
SendResult<String, String> sendResult = future.get(10, TimeUnit.SECONDS);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Thread.currentThread.interrupt();
}
catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (TimeoutException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

Kafkaproducer.send returns a future. If you want to wait then perhaps you would prefer the following:
kafkaProduc.send("topictest", msg).get(1L, TimeUnit.SECONDS);
Then failures are likely to raise an exception rather than invoking your on error callback.

JMeter does not execute Java code correctly if it's ran as .jar file from command line

I'm designing JMeter scenario which implies executing a certain .jar file via OS Process Sampler element. My Java code has while loop which basically checks a certain mailbox for a letter with a certain subject. Loop waits until finds one (emails are always delivered with roughly 3 minutes delay), parses it and writes some data to .txt file.
If I run this .jar directly from cmd then the code works as expected. But if I run it via JMeter OS Process Sampler then it never creates a file for me. I do see that email is delivered to inbox, so expect it to be parsed and .txt created.
At first I suspected that JMeter finishes Java scenario without waiting for while loop to execute. Then I put OS Process Sampler in a separate Thread and added a huge delay for this thread in order to wait and make 100% sure that email is delivered and Java only need to parse it but it does not help.
View Results Tree never shows any errors.
Here is my OS Process Sampler: https://www.screencast.com/t/LomYGShJHAkS
This is what I execute via cmd and it works as expected: java -jar mailosaurJavaRun.jar email533.druzey1a#mailosaur.in
And here is my code (it does not looks good but it works):
public class Run {
public static void main(String[] args) {
MailosaurHelper ms = new MailosaurHelper();
String arg1 = ms.getFirstLinkInEmail(args[0]);
BufferedWriter output = null;
try {
File file = new File("url.txt");
output = new BufferedWriter(new FileWriter(file));
output.write(arg1);
} catch ( IOException e ) {
e.printStackTrace();
} finally {
if ( output != null ) {
try {
output.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
public class MailosaurHelper {
protected final String API_KEY = "b3e4d2b193b5eb2";
protected final String MAILBOX_ID = "d1uzey1a";
public MailboxApi getEmailBox() {
return new MailboxApi(MAILBOX_ID, API_KEY);
}
public String getFirstLinkInEmail(String email) {
MailosaurHelper ms = new MailosaurHelper();
String link = "";
if (link.equals("") || link.isEmpty()) {
try {
Thread.sleep(3000);
link = ms.getAllEmailsByReceipent(email)[0].html.links[0]
.toString();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return link;
}
public Email[] getAllEmailsByReceipent(String recepient) {
try {
int ifArrayIsEmpty = getEmailBox().getEmailsByRecipient(recepient).length;
while (ifArrayIsEmpty == 0) {
try {
Thread.sleep(3000);
ifArrayIsEmpty = getEmailBox().getEmailsByRecipient(
recepient).length;
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} catch (MailosaurException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
Email[] listOfEmails = null;
try {
listOfEmails = getEmailBox().getEmailsByRecipient(recepient);
} catch (MailosaurException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return listOfEmails;
}
The bottom line is that I need to parse Mailosaur email, retrieve URL from it and use it further. Any other suggestion on how to do that using Jmeter/Java/Mailosaur are appreciated.

You don't need cmd in here, but if you're adamant to stick with it - use /C key when you call it.
Then, are your sure you're looking for your file in the right place?
According to documentation:
By default the classes in the java.io package always resolve relative
pathnames against the current user directory. This directory is named
by the system property user.dir, and is typically the directory in
which the Java virtual machine was invoked.
Check it thoroughly, BTW - you should see it in your sampler result.

Java ExecutorService REST call error

I am trying to use Java's ExecutorService to send out concurrent REST requests which make various logs of system information (coming from a controller), however am running into a bug. About half of my requests successfully make it to the target, but the other half appear as if they are sent, but are not found on the server they were sent to. I think I may have a flaw in the logic of setting up my ExecutorService. The function log() shown below can be called from a REST call to the controller, and is supposed to create a new thread which sends out a separate HTTP request, and continue with the main thread so as not to wait for the network I/O. After much searching, I believe I have the ExecutorService shutdown properly an wait for the thread to complete. Can anybody see some type of error in the logic of my thread creation, as multiple requests from the controller can continue to come in?
//Controller
//code
#RequestMapping(value="/log", method= RequestMethod.GET)
public String log()
{
genomicsLogger.log(Severity.err, Category.LOG, "This is a log from the reporting manager!");
return "Hopefully logged";
}
//ClassB
public String log(String trns , String user, Severity severity, Category category, String msg) {
trnsField = trns;
userField = user;
...
...
...
ExecutorService executor = Executors.newFixedThreadPool(1);
Runnable task = () -> {
try {
System.out.println("Started thread: " + Thread.currentThread().getName());
restService.consumeRest(true, instance.getUri().toString(), LOG_URI, list, log, HttpMethod.POST, new HttpHeaders(), String.class);
System.out.println("SENT REST REQUEST");
} catch (URISyntaxException e) {
e.printStackTrace();
} catch (KeyStoreException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (CertificateException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (UnrecoverableKeyException e) {
e.printStackTrace();
} catch (KeyManagementException e) {
e.printStackTrace();
}
}
};
executor.submit(task);
try {
System.out.println("attempt to shutdown executor");
executor.shutdown();
executor.awaitTermination(5, TimeUnit.SECONDS);
}
catch (InterruptedException e) {
System.err.println("tasks interrupted");
}
finally {
if (!executor.isTerminated()) {
System.err.println("cancel non-finished tasks");
}
executor.shutdownNow();
System.out.println("shutdown finished");
}
return "";
}

You are creating executor service with each log and killing it.
This is not the way to use it, it is meant to be reused, make it e.g. a field in this class and set some number of threads that you are willing to use for it (probably higher than 1). And don't do shutdown on it until you are really sure it won't be used (e.g. during application shutdown).

Producer Consumer in Java using threads never terminates

I have a Producer-Consumer problem to implement in Java, where I want the producer thread to run for a specific amount of time e.g. 1 day, putting objects in a BlockingQueue -specifically tweets, streamed from Twitter Streaming API via Twitter4j- and the consumer thread to consume these objects from the queue and write them to file. I've used the PC logic from Read the 30Million user id's one by one from the big file, where producer is the FileTask and consumer is the CPUTask (check first answer; my approach uses the same iterations/try-catch blocks with it). Of course I adapted the implementations accordingly.
My main function is:
public static void main(String[] args) {
....
final int threadCount = 2;
// BlockingQueue with a capacity of 200
BlockingQueue<Tweet> tweets = new ArrayBlockingQueue<>(200);
// create thread pool with given size
ExecutorService service = Executors.newFixedThreadPool(threadCount);
Future<?> f = service.submit(new GathererTask(tweets));
try {
f.get(1,TimeUnit.MINUTES); // Give specific time to the GathererTask
} catch (InterruptedException | ExecutionException | TimeoutException e) {
f.cancel(true); // Stop the Gatherer
}
try {
service.submit(new FileTask(tweets)).get(); // Wait til FileTask completes
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
service.shutdownNow();
try {
service.awaitTermination(7, TimeUnit.DAYS);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
Now, the problem is that, although it does stream the tweets and writes them to file, it never terminates and never gets to the f.cancel(true) part. What should I change for it to work properly? Also, could you explain in your answer what went wrong here with the thread logic, so I learn from my mistake? Thank you in advance.
These are the run() functions of my PC classes:
Producer:
#Override
public void run() {
StatusListener listener = new StatusListener(){
public void onStatus(Status status) {
try {
tweets.put(new Tweet(status.getText(),status.getCreatedAt(),status.getUser().getName(),status.getHashtagEntities()));
} catch (InterruptedException e) {
e.printStackTrace();
Thread.currentTread.interrupt(); // Also tried this command
}
}
public void onException(Exception ex) {
ex.printStackTrace();
}
};
twitterStream.addListener(listener);
... // More Twitter4j commands
}
Consumer:
public void run() {
Tweet tweet;
try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("out.csv", true)))) {
while(true) {
try {
// block if the queue is empty
tweet = tweets.take();
writeTweetToFile(tweet,out);
} catch (InterruptedException ex) {
break; // GathererTask has completed
}
}
// poll() returns null if the queue is empty
while((tweet = tweets.poll()) != null) {
writeTweetToFile(tweet,out);
}
} catch (IOException e) {
e.printStackTrace();
}
}

You should check if your Thread classes are handling the InterruptedException, if not, they will wait forever. This might help.