Hi David,

Thanks for the quick response. Here is a small sample project: 
https://bitbucket.org/sandermak/javafx-application/src, the compilerun.sh can 
be used to start the app. I already alluded to the solution you propose in the 
original post. Indeed, when exporting the class that extends Application 
(qualified to javafx.graphics or not, both will do) it works.

However, is such an application class really something I want to export to 
other modules? Of course using a qualified export the scope can be restricted 
to the javafx.graphics module, and that's what I ended up doing. In general, I 
think it's interesting  that many frameworks want reflective access to what are 
essentially internal implementation classes. Spring comes to mind, you'd want 
to export interfaces but not Spring bean implementation classes, even though 
the framework needs access to instantiate them. As has been discussed before on 
this list, ServiceLoader has a special super-power in this regard, and I sort 
of expected JavaFX Application handling to have that same superpower for 
instantiating the Application class.

One more follow-up question: when I remove the main() method that invokes 
launch (see here: 
https://bitbucket.org/sandermak/javafx-application/diff/src/applicationmodule/application/Main.java?diff2=fca74ffbc28d&at=without-main),
 the following error comes up (build 9-ea+106-jigsaw-nightly-h4498-20160221):

Error: Main method not found in class application.Main, please define the main 
method as:
   public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application

On JDK8 the same code runs fine. What's going on there?


Thanks,
Sander

On 23 Feb 2016, at 22:46, David Hill 
<david.h...@oracle.com<mailto:david.h...@oracle.com>> wrote:

On 2/23/16, 3:37 PM, Sander Mak wrote:
Hi,

Sander,
   we may not have tested Jigsaw with the path you are trying to take here.

Certainly the common path of a class extending Application will launch 
properly, and I have been trudging through our test cases working on some odder 
paths. What I have not been doing in these paths is dealing with a new module, 
though I would think that would behave similarly to the unnamed module.

It could be that your added complexity here has not been properly dealt with in 
our FX code.

Do you have a "simple" test case that shows this error?

Looking at the exception I see a lot of stuff going on, and it is hard to see 
the root right away.

With modules, we have to add read edge code in certain spots when our code has 
to reach out of the module to a module it does not already know about.

This is the hint here:

(in module javafx.graphics) cannot access class 
javamodularity.easytext.gui.Main (in module javamodularity.easytext.gui)

Our FX module javafx.graphics cannot see into your module.

The question becomes one of where, and order of operations.

Dave



When trying to run a module with a main class that extends 
javafx.application.Application, the following exception is thrown by the VM:

Exception in thread "main" java.lang.RuntimeException: Unable to construct 
Application instance: class javamodularity.easytext.gui.Main
at 
com.sun.javafx.application.LauncherImpl.launchApplication1(javafx.graphics@9-ea/LauncherImpl.java:926)
at 
com.sun.javafx.application.LauncherImpl.lambda$launchApplication$140(javafx.graphics@9-ea/LauncherImpl.java:220)
at java.lang.Thread.run(java.base@9-ea/Thread.java:804)
Caused by: java.lang.IllegalAccessException: class 
com.sun.javafx.application.LauncherImpl (in module javafx.graphics) cannot 
access class javamodularity.easytext.gui.Main (in module 
javamodularity.easytext.gui) because module javamodularity.easytext.gui does 
not export javamodularity.easytext.gui to module javafx.graphics
at 
sun.reflect.Reflection.throwIllegalAccessException(java.base@9-ea/Reflection.java:465)
at 
sun.reflect.Reflection.throwIllegalAccessException(java.base@9-ea/Reflection.java:456)
at sun.reflect.Reflection.ensureMemberAccess(java.base@9-ea/Reflection.java:98)
at 
java.lang.reflect.AccessibleObject.slowCheckMemberAccess(java.base@9-ea/AccessibleObject.java:370)
at 
java.lang.reflect.AccessibleObject.checkAccess(java.base@9-ea/AccessibleObject.java:362)
at 
java.lang.reflect.Constructor.newInstance(java.base@9-ea/Constructor.java:435)
at 
com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$146(javafx.graphics@9-ea/LauncherImpl.java:838)
at 
com.sun.javafx.application.PlatformImpl.lambda$runAndWait$160(javafx.graphics@9-ea/PlatformImpl.java:351)
at 
com.sun.javafx.application.PlatformImpl.lambda$null$158(javafx.graphics@9-ea/PlatformImpl.java:320)
at java.security.AccessController.doPrivileged(java.base@9-ea/Native Method)
at 
com.sun.javafx.application.PlatformImpl.lambda$runLater$159(javafx.graphics@9-ea/PlatformImpl.java:319)
at 
com.sun.glass.ui.InvokeLaterDispatcher$Future.run(javafx.graphics@9-ea/InvokeLaterDispatcher.java:96)

This can be solved by adding a (qualified) export in the module-info of the 
module I'm trying to run (inspired by the helpful error message, nice!):

exports javamodularity.easytext.gui to javafx.graphics;

However, that's not really a satisfactory solution. Looks like LauncherImpl 
also needs to setup a readability relation on-the-fly, with the caveat that the 
class extending Application must always be exported by the application 
developer for this to work. Is this the solution we can expect, or are there 
any other plans for this situation?


Regards,
Sander


--
David Hill<david.h...@oracle.com<mailto:david.h...@oracle.com>>
Java Embedded Development

"A man's feet should be planted in his country, but his eyes should survey the 
world."
-- George Santayana (1863 - 1952)

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