JavaFX Launch Failure on Ubuntu from JNI

[Steve Hannah]

Thanks for the reply.

>  What are the JVM args you use for launching?

vm_args.version = JNI_VERSION_1_6;
  vm_args.options = options;
  vm_args.nOptions = numOptions;
  vm_args.ignoreUnrecognized = 1;

For options, I'm just using -Djava.class.path, though I have experimented
using -Djavafx.verbose=true, which doesn't tell me much more.  It just logs
warnings when it can't find the javafx nativelibs, in the JDK libs
directory - and reports that they are loaded from resource.

>  Are the JavaFX modules jlink'ed into the JDK or loaded via
--module-path?

They are included in the classpath.  I'm not using modules.

Best regards

Steve

On Wed, Jan 19, 2022 at 10:35 AM Kevin Rushforth <kevin.rushforth at oracle.com>
wrote:

> Hard to say what's going on without more information. What are the JVM
> args you use for launching? Are the JavaFX modules jlink'ed into the JDK
> or loaded via --module-path? As a debugging aid, you might try setting
> the system property "javafx.verbose" to "true" before loading your
> MyApplication class.
>
> -- Kevin
>
>
> On 1/19/2022 9:40 AM, Steve Hannah wrote:
> > The following issue only seems to occur on Linux (Ubuntu 20.04.1), and
> only
> > when I try to launch the JVM from a custom C launcher using JNI.  It does
> > not occur when launching the JVM as a separate process using the "java"
> > binary.  It also does not occur on MacOS when using the same C launcher
> > using JNI.
> >
> > When I call MyApplication.launch(args). (where MyApplication extends the
> > JavaFX Application class), I get the following stack trace:
> >
> > Jan. 19, 2022 8:54:27 A.M. com.sun.javafx.application.PlatformImpl
> startup
> > Exception in thread "Thread-5" java.lang.IllegalStateException: This
> > operation is permitted on the event thread only; currentThread =
> > Thread-5
> >          at
> com.sun.glass.ui.Application.checkEventThread(Application.java:447)
> >          at com.sun.glass.ui.Application.setName(Application.java:200)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$setApplicationName$2(PlatformImpl.java:142)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
> >          at java.base/java.security.AccessController.doPrivileged(Native
> Method)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
> >          at
> com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
> > Exception in Application start method
> > Exception in thread "Thread-31" Failed to show docs
> > java.lang.IllegalStateException: Not on FX application thread;
> > currentThread = Thread-31
> >          at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:295)
> >          at
> com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:458)
> >          at
> com.sun.javafx.tk.quantum.QuantumToolkit.exit(QuantumToolkit.java:828)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$tkExit$16(PlatformImpl.java:624)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:484)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
> >          at java.base/java.security.AccessController.doPrivileged(Native
> Method)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
> >          at
> com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
> > java.lang.RuntimeException: Exception in Application start method
> >          at
> com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:901)
> >          at
> com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:196)
> >          at java.base/java.lang.Thread.run(Thread.java:829)
> > Caused by: java.lang.IllegalStateException: Not on FX application
> > thread; currentThread = Thread-6
> >          at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:295)
> >          at
> com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:458)
> >          at javafx.stage.Stage.<init>(Stage.java:254)
> >          at javafx.stage.Stage.<init>(Stage.java:240)
> >          at
> com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:845)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:484)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
> >          at java.base/java.security.AccessController.doPrivileged(Native
> Method)
> >          at
> com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
> >          at
> com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
> >
> >
> > I have tried a few different versions of JavaFX (11, 11.0.2, 17.0.1),
> > running on a few different JDK installs (all JDK11).  Above stacktrace is
> > from 17.0.1.
> >
> >  From the C application that launches the JVM, I have tried running
> directly
> > on the main thread, and also launching it in a fresh thread using
> pthreads
> > - but same issue.  I am running this inside an application written in Go
> > but the JNI code is all in C.
> >
> > It appears as though JavaFX is unable to create its application thread
> for
> > some reason.  Does anyone have any suggestions on reasons why this would
> be
> > the case?  Are there some system properties that need to be there which
> > would have been bootstrapped by the "java" binary, but would not when the
> > JVM is launched via JNI?
> >
> > Any suggestions appreciated.  I've been banging my head on this for a
> while
> > now.
> >
> > Best regards
> >
> > Steve
>
>

-- 
Steve Hannah
Web Lite Solutions Corp.