B4J Question B4JPackager and "WARNING: An illegal reflective access operation has occurred"

[drponciano]

My program works fine with no warnings if I complie with JDK from Oracle but, if I compile with OpenJDK 11, I get the "Illegal reflective..." warning after a few iterations. That is not a problem when I'm running the app from Java "java -jar myapp.jar" but, if I use B4J Packager, when running the EXE, the program stops after the warning.
Any idea how can I avoid the warning or what is causing it?

 

[Erel]

Please post the full output from run_debug.bat.

 

[drponciano]

Running from B4J UI the warning is also present in the log area but the program keeps working fine. Not the case with the EXE. Here is the output from run_debug.bat:

Recibo RED 63
PROM 1
Fin de Newdata RED
IRR Instantáneo 154
main._beep (java line: -1)
java.lang.IllegalAccessException: class anywheresoftware.b4j.object.JavaObject (in module b4j) cannot access class sun.awt.windows.WToolkit (in module java.desktop) because module java.desktop does not export sun.awt.windows to module b4j
at java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Unknown Source)
at java.base/java.lang.reflect.AccessibleObject.checkAccess(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at b4j/anywheresoftware.b4j.object.JavaObject.RunMethod(Unknown Source)
at b4j/b4j.example.main._beep(Unknown Source)
at b4j/b4j.example.main._timer_principal_tick(Unknown Source)
at jdk.internal.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at b4j/anywheresoftware.b4a.BA.raiseEvent2(Unknown Source)
at b4j/anywheresoftware.b4a.objects.Timer$TickTack$1.run(Unknown Source)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(Unknown Source)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(Unknown Source)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)


C:\Fuentes\Basic4Mac\ZiECG_JV\Objects\temp\build\bin>pause
Presione una tecla para continuar . . .

 

[Erel]

Best to upload a small project that demonstrates it.

 

[drponciano]

I found the problem! Now, is there a solution?
The warning is issued the first time the beep routine is called:

Sub Beep
   Dim jo As JavaObject
   jo.InitializeStatic("java.awt.Toolkit")
   Dim toolkit As JavaObject = jo.RunMethod("getDefaultToolkit", Null)
   toolkit.RunMethod("beep", Null)
End Sub

 

[NikB4x]

I found the problem! Now, is there a solution?
The warning is issued the first time the beep routine is called:

Sub Beep
   Dim jo As JavaObject
   jo.InitializeStatic("java.awt.Toolkit")
   Dim toolkit As JavaObject = jo.RunMethod("getDefaultToolkit", Null)
   toolkit.RunMethod("beep", Null)
End Sub

Hi @drponciano,
just a curiosity of mine ... why are you using the toolkit's beep method to reproduce the sound?

 

[drponciano]

Hi @drponciano,
just a curiosity of mine ... why are you using the toolkit's beep method to reproduce the sound?

Yes, thas was one method sugested by Erel long time ago ?. It's working fine, but now... Any suggestion?

 

[NikB4x]

If you don't want use mediaplayer, have you tried this: http://stackoverflow.com/questions/30377129/playing-audio-on-raspberry-pi-with-java
also suggested by Erel

 

[Erel]

Change your code to:

Sub Beep
    Dim jo As JavaObject = Me
    jo.RunMethod("beep", Null)
End Sub

#if Java
public static void beep() {
    java.awt.Toolkit.getDefaultToolkit().beep();
}
#End If

 

[agraham]

Just out of curiosity why does the inline Java work when the apparently identical JavaObject code doesn't? Something not public or am I missing the obvious?

 

[Erel]

Nothing obvious here.

It is related to getDefaultTookit returning sun.awt.windows.WToolkit which is public by itself but is from a closed module.