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InteliJ JavaFX displaying blank white screen when booting

I'm trying to get a starter project for a template running over for JavaFX, the assignment is to get a hello world program up and running using JavaFX to get the program running.
(Some Background context: We're using IntelliJ for our class assignment, but recently we found out that it seems(?) support for JavaFx has been discontinued within InteliJ, regardless the same assignment remains so we installed a third party library following the steps over from a guide about getting the library, ( How to get JavaFX and Java 11 working in IntelliJ IDEA ), the instructions helped to get the program running and compiled and I used the paths out, but when I ran the program, I got a blank white screen, and I have no clue if this is normal or not.)
The code is just the default JavaFX template from Intllij, I've tried installing the SDKS and JDKS (which seemed to help the program compile), but when running, I just get a blank white screen.
Here is a screenshot of the white screen problem https://i.imgur.com/7ZYju3M.jpg
And the code below; it's just a IntelliJ default startup, but I don't know why it doesn't work.
package sample;
// Original Imports found in testTemplate
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
#Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
package sample;
public class Controller {
}
We expected the results to say hello world. I think so anyways, but I actually have no clue what it's supposed to look like as it's my first time, I think it's supposed to say hello world. (Later on, we're supposed to get the GUI configured, but for right now, I just want to figure out what's going wrong with the program.)

Trouble with Selenium, Java, Screenshots and clicking buttons

This is another question about Selenium and clicking. I have been struggling for about two days and can't get it to work - I have tried the answers in the internet and now I need a concerted effort. Thanks in Advance!!
I am working on the following site http://144.76.109.38/peTEST - this might help if you want to retrace my steps.
I am trying to fill out the login form, and then click on Login and see the answer page.
Here is my code:
import java.io.File;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.Writer;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
import org.openqa.selenium.By;
import org.openqa.selenium.Keys;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.ExpectedCondition;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.openqa.selenium.support.ui.Select;
public class toJava {
public static void main(String[] args) {
System.setProperty("webdriver.gecko.driver","/home/tallen/RTI/lib/geckodriver/geckodriver");
WebDriver driver = new FirefoxDriver();
driver.get("http:144.76.109.38/peTEST");
File SF2 = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
try{
FileUtils.copyFile(SF2, new File("./out-004.png"));
}catch(IOException ioe){
System.out.println("There was an IO error");
}
driver.findElement(By.id("user_login_name")).click();
WebElement WE4 = driver.findElement(By.id("user_login_name"));
WE4.sendKeys("Superuser");
driver.findElement(By.id("user_password")).click();
WebElement WE6 = driver.findElement(By.id("user_password"));
WE6.sendKeys("Jkerouac1!");
WebElement WE7 = driver.findElement(By.xpath(".//*[#type='button'][#onclick='login()'][#value='Login']"));
WE7.sendKeys(Keys.ENTER);
File SF8 = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
try{
FileUtils.copyFile(SF8, new File("./out-005.png"));
}catch(IOException ioe){
System.out.println("There was an IO error");
}
driver.quit();
}
}
So basically I am opening up the page, taking a screenshot entering the user name and password, clicking Login and then taking another screenshot.
The compile and the run on this are clean - that is no exceptions and no problems. I even get two screenshots. The first screenshot shows the login page - with no data entered. The second screenshot shows the login page filled, the button I want to click marked, but not the "welcome Page" that you would get if you successfully log in. That the screenshot shows the button marked, I know that I have found the element. I have give the login info in the script, in case you want to try it out with Selenium first.
Why is the login button not being "clicked." I have tried click, perform, etc. to no avail. I have even tried putting in implicit waits - still nothing.
I have tried to Advanced Usage Interactions - and still nothing.
I am pretty new to Selenium and Java and am hoping that it is just something stupid that I am overlooking. But after looking through the Web, the solutions there are just not helping.
I am working on Debian-70-Wheezy-64-LAMP
My Selenium Libraries are from client-combined-3.0.1-nodeps.jar
My Geckodriver is v0.11.1-linux64
Thanks for the Help!!!

Hi, I don't know if it can cause a problem but anyway for the login button I would use WE7.click(); I just think that it's easier to understand what you're trying to do with the element.
I've been working with the GeckoDriver for a while and talking with some experienced people in the area and they told me that Gecko has many problems that are not fixed yet.
They always recommended me not to use GeckoDriver because it seems to fail very often and told me to use FirefoxDriver instead.
To try it this way, and this is important, you'll just need to keep working with an older version of Firefox as the version 46 that is compatible with FirefoxDriver (that version worked for me and you can download it from places like this) and avoid using GeckoDriver.
Also the version 47 seems to work with the FirefoxDriver as I've found here.
Remember: When you install one of these previous versions of Firefox, don't forget to go to settings and disable the automatic updates and background updates because if you don't do this, you'll end soon again with the latest version that requires GeckoDriver.
In addition you can try some validation as the following:
if(WE7.isDisplayed() && WE7.isEnabled()){
WE7.click();
}
This kind of validations would help in case that the page isn't fully loaded at the moment that you're trying to take action over the web element. If the element is not ready, you will click it without errors but it just won't work
Hope this works for you too!

Linux Mint Cinnamon Lock-Up Debugging w/Eclipse

I have a reproducible problem with the Mint Cinnamon desktop locking up when hitting a breakpoint debugging with Eclipse. When I say it's locking up, I mean mouse clicks are completely inoperable (even on the Mint panel), but the mouse cursor still moves. Keyboard is unresponsive, except for some OS-level shortcuts like Alt-Tab. Alt-Tab looks like it's working, but selecting another window doesn't actually focus or activate the window (only the Alt-Tab selector popup works). I can only recover using Ctrl-Alt-ESC to restart Cinnamon. Everything proceeds fine after that.
Debugging and breakpoints work fine everywhere else as far as I can tell except when the breakpoint is inside an anon inner class or lambda.
Public git repo with a fairly simple example project causing this:
https://bitbucket.org/jfxexamples/eclipseminttest
Linux Mint 17.3 AND a totally new install of Mint 18 on a different PC - both behave the same
Eclipse Neon 4.6.0
Java 8 (1.8.0_92) - Oracle JDK (Using JavaFX)
Code below (you'll have to grab the project files to run it though):
package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class Main extends Application {
#Override
public void start(Stage primaryStage) {
try {
BorderPane root = (BorderPane)FXMLLoader.load(getClass().getResource("Sample.fxml"));
Scene scene = new Scene(root,400,400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
launch(args);
}
}
package application;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
public class SampleController {
#FXML
private TabPane tabPane;
public void createTab() {
Tab tab = new Tab("New tab");//Breakpoint here does NOT freeze desktop
// tab.setOnCloseRequest(e -> {
// System.out.println("bleh");//Breakpoint here, freezes desktop
// });
tab.setOnCloseRequest(new EventHandler<Event>(){
#Override public void handle(Event e){
System.out.println("bleh");//Breakpoint here, also freezes desktop
}
});
tabPane.getTabs().add(tab);//Breakpoint here does NOT freeze desktop
int index = tabPane.getTabs().size() - 1;
tabPane.getSelectionModel().select(index);
}
}

Using Win10/IntellijCE/JDK1.8.0_92 there is no problem. Try using IntellijCE on Mint. If it works the problem is most likely with Cinnamon.
Cinnamon is on Github, so use their Issue Tracker there to report the bug.
Browsing the issues, there is even something maybe related to your issue: Check out https://github.com/linuxmint/Cinnamon/issues/1084.

I have had exactly the same problem in Linux Mint 17.3 Mate, with JDK 1.8.0_101, Eclipse Neon and a JavaFX application.
When debugging the application, the system freezes completely and I have to kill the process manually.
It seems a problem related with the X display. It should work if you set, in the VM arguments of your application, the flag:
-Dsun.awt.disablegrab=true
At least that worked for me...

This is a known problem on Linux. It is related to the XGrabPointer and XGrabKeyboard API calls (see X Pointer Grabbing). This API can be used by screensavers, so it is intended to make the keyboard and mouse unusable (apart from moving the mouse cursor).
During debugging, it is a problem. In the past, a workaround was to configure AllowDeactivateGrabsin xorg. That allowed to break the "grap" by a keyboard shortcut, by default CTRL+ALT+/. Since it was possible to bypass screensavers, it was disabled around 2012 because of its security implications.
On a modern Linux system, you can enable enable grab break actions:
setxkbmap -option grab:break_actions
Now, you can trigger a grab break by executing:
xdotool key XF86Ungrab
Once your keyboard is frozen, you might be not able to run it, so during debugging, I am calling it every two seconds:
while :; do sleep 2 ; xdotool key XF86Ungrab ; done
Notes:
setxkbmap is part of xorg-setxkbmap
xdotool is part of xdotool
While testing the setup, it is useful to have a ssh connection from another machine. Thus, if mouse and keyboard freeze up, you can always kill the process that grabbed the mouse and keyboard.

How to force ImageJ to close all its windows without close event error?

I am writing a Java application for image analysis which at one point opens ImageJ with
ImageJ ij = new ImageJ();
and also opens a Windows containing an ImagePlus.
Now, whenever one closes ImageJ first, the ImagePlus will not close when pushing the close button. The other way around works, however in both cases an exception is thrown after closing ImageJ:
java.lang.reflect.InvocationTargetException
at java.awt.EventQueue.invokeAndWait(EventQueue.java:1288)
at java.awt.Window.doDispose(Window.java:1209)
at java.awt.Window.dispose(Window.java:1147)
at ij.ImageJ.run(ImageJ.java:784)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: null source
at java.util.EventObject.<init>(EventObject.java:56)
at java.awt.AWTEvent.<init>(AWTEvent.java:337)
at java.awt.event.InvocationEvent.<init>(InvocationEvent.java:285)
at java.awt.event.InvocationEvent.<init>(InvocationEvent.java:174)
at sun.awt.X11.XBaseMenuWindow.dispose(XBaseMenuWindow.java:907)
...
I don't know whether it is related as it happens in both cases.
Any suggestions on how to force ImageJ to close all its windows?

The exception
This happens when using OpenJDK 7 on Linux. The exception is fixed in Java 8.
Also: note that that exception is not the actual cause of the quitting issue you are seeing.
The disposal problem
ImageJ 1.x's application disposal is a convoluted mess. (See this news post for some technical discussion.) It was really intended primarily to run as a standalone application, and is mostly tested with the exitWhenQuitting flag set to true such that the JVM shuts down upon closure of the main window. So it is not surprising that using ImageJ in a different fashion results in hanging image windows.
I have tested various workarounds—e.g.:
ij.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(final WindowEvent e) {
// dispose all image windows
for (final int id : WindowManager.getIDList()) {
final ImagePlus imp = WindowManager.getImage(id);
if (imp == null) continue;
final ImageWindow win = imp.getWindow();
if (win != null) win.dispose();
}
// dispose all other ImageJ windows
for (final Window w : WindowManager.getAllNonImageWindows()) {
w.dispose();
}
}
});
But none of them work as one might hope. It cost me weeks of development and experimentation to make quitting work as we wanted in ImageJ2, according to the news posted linked above.
Here is some code using ImageJ2 that almost behaves the way you want:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.WindowConstants;
import net.imagej.ImageJ;
public class IJDispose {
public static void main(final String... args) {
final ImageJ ij = new ImageJ();
ij.ui().showUI();
final JFrame frame = new JFrame("Hello");
final JButton b = new JButton("Close ImageJ");
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
ij.getContext().dispose();
}
});
frame.getContentPane().add(b);
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
After launching it, press Shift+B to open the Blobs sample image. Then click the "Close ImageJ" button from the non-ImageJ frame. You'll see that the ImageJ main window and the image window dispose as desired (using this code from ImageJ Legacy).
However, there are (at least) three problems:
This example does not hook up the ij.getContext().dispose() call to the actual ImageJ1 UI window closing event. And doing that would not be trivial (I say without having dug deeply in this code recently).
After disposing ImageJ, as well as the extra JFrame, the JVM is supposed to shut down. We put a lot of effort into making it do so, actually. But it actually doesn't with the current version of ImageJ, presumably due to some undisposed resource(s) somewhere. This is a bug.
Clicking the X on the main ImageJ window shuts down the entire JVM, because ImageJ1's exitWhenQuitting flag gets set to true. You could toggle it back to false yourself, but this is actually tricky due to class loading issues relating to the fact that ImageJ2 patches ImageJ1 at runtime using Javassist.
The next question is: How badly do you really need this to work?

Runtime problems with HelloWorldSWT eclipse

I just downloaded Eclipse and was doing the HelloWorldSWT tutorial to familiarize myself with the IDE.
The program runs, but contrary to having display.sleep() in the main loop, the program continues to eat up CPU cycles. Is this normal for this tutorial? and how can I prevent this?
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
public class HelloWorldSWT {
/**
* #param args
*/
public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setText("Hello world!");
shell.open();
while(!shell.isDisposed()){
display.sleep();
}
display.dispose();
shell.close();
}
}
Edit: I've found that
if (!display.readAndDispatch()) {display.sleep();}
resolves the issue. However, I still do not understand the difference between checking for nonexistant events and then telling the display to sleep and just telling the display to sleep that would cause this issue.

You need to call display.readAndDispatch() to read the events from the event queue and act on them (dispatch).
Even the the deactivate event from the Shell must be dispatched!
All SWT based application have an event loop as the one you have added to your post. Have a look at the SWT Snippets for more examples.

It is how you create the project that is causing this. The correct relationships need to be applied at the start with dependencies set and libraries set.
I got it working then played around with it to see what was underlying cause as there are a lot of blogs with various tips that worked with some people and not with others.
Main point is this is necessary
import org.eclips.swt.widget.Display
import org.eclips.swt.widget.Screen