B4J Question Error WriteToStream And AWT on raspberry

[micro]

Hello everyone
I need remotely to have a simple screen replication of a raspberry LCD, the connection between server (Raspy) and client (Pc) is done with mqtt protocol.
If I use it (server) on desktops (win10) everything works perfectly but on the raspberry I fail in the following lines of code:
This is the frame capture part
I have two possibilities one complete that also shows notifications and everything overlapping on the main, the other just the main.
Capture only Main:

Sub CatturaImg
    Dim out As OutputStream
    out.InitializeToBytesArray(0)
    Dim img As Image = Main.MainForm.RootPane.Snapshot
    If img.IsInitialized = False Then Return
    img.WriteToStream(out) '<----------Error'
    out.Close
    Dim cc As CompressedStreams
    SendFrame(cc.CompressBytes(out.ToBytesArray,"zlib").As(Object))
End Sub

Connected mqtt
mqttserv._catturaimg (java line: 63)
java.lang.NoClassDefFoundError: javafx/embed/swing/SwingFXUtils
    at anywheresoftware.b4j.objects.ImageViewWrapper$ImageWrapper.WriteToStream(ImageViewWrapper.java:199)
    at b4j.SepPi.mqttserv._catturaimg(mqttserv.java:63)
    at b4j.SepPi.mqttserv.callSub(mqttserv.java:356)
    at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:498)
    at anywheresoftware.b4a.keywords.Common.CallSubNew(Common.java:461)
    at b4j.SeparatorePi.mqttserv._timer1_tick(mqttserv.java:349)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)
    at anywheresoftware.b4a.objects.Timer$TickTack$1.run(Timer.java:135)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.monocle.RunnableProcessor.runLoop(RunnableProcessor.java:92)
    at javafx.graphics/com.sun.glass.ui.monocle.RunnableProcessor.run(RunnableProcessor.java:51)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.ClassNotFoundException: javafx.embed.swing.SwingFXUtils
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 18 more

It doesn't load the swing class?
'
Capture All:

Sub CatturaImg
    Dim awt As AWTRobot
    awt.ScreenCurrentRectangleSetAsArbitrary(Main.MainForm.WindowLeft,Main.MainForm.WindowTop,Main.MainForm.WindowWidth,Main.MainForm.WindowHeight)
    Dim cc As CompressedStreams
    SendFrame(cc.CompressBytes(awt.ScreenCaptureAsByteArray,"zlib").As(Object))
End Sub

Error when loading awt class?

Connected mqtt
java.awt.AWTException: headless environment
    at java.desktop/java.awt.Robot.<init>(Robot.java:94)
    at butt.droid.awtRobot.AWTRobot.<init>(AWTRobot.java:91)
    at b4j.SepPi.mqttserv._catturaimg(mqttserv.java:72)
    at b4j.SepPi.mqttserv.callSub(mqttserv.java:356)
    at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:498)
    at anywheresoftware.b4a.keywords.Common.CallSubNew(Common.java:461)
    at b4j.SeparatorePi.mqttserv._timer1_tick(mqttserv.java:349)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)
    at anywheresoftware.b4a.objects.Timer$TickTack$1.run(Timer.java:135)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.monocle.RunnableProcessor.runLoop(RunnableProcessor.java:92)
    at javafx.graphics/com.sun.glass.ui.monocle.RunnableProcessor.run(RunnableProcessor.java:51)
    at java.base/java.lang.Thread.run(Thread.java:834)
mqttserv._timer1_tick (java line: 349)
java.lang.RuntimeException: java.lang.NullPointerException
    at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:523)
    at anywheresoftware.b4a.keywords.Common.CallSubNew(Common.java:461)
    at b4j.SeparatorePi.mqttserv._timer1_tick(mqttserv.java:349)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)
    at anywheresoftware.b4a.objects.Timer$TickTack$1.run(Timer.java:135)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.monocle.RunnableProcessor.runLoop(RunnableProcessor.java:92)
    at javafx.graphics/com.sun.glass.ui.monocle.RunnableProcessor.run(RunnableProcessor.java:51)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.NullPointerException
    at butt.droid.awtRobot.AWTRobot.ScreenCaptureAsByteArray(AWTRobot.java:858)
    at b4j.SepPi.mqttserv._catturaimg(mqttserv.java:78)
    at b4j.SepPi.mqttserv.callSub(mqttserv.java:356)
    at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:498)
    ... 14 more

How can I fix this?
Thanks

Foreword
I do not boot x windows on raspberry, my program starts it in console mode automatically with the following line in crontab:

@reboot sudo /usr/lib/jvm/jdk-11.0.1/bin/java -jar /home/pi/Xxxxx/Xxxxx.jar

 

[micro]

Other test done in desktop mode by starting startx:
With Awt the program works only that the captured screens are only those of the raspberry desktop but not of the program even though it is visible in the foreground.
With the other mode the program crashes with the same problem
"
java.lang.NoClassDefFoundError: javafx/embed/swing/SwingFXUtils
......
......

 

[Knoppi]

it looks like you don't have JFX installed on your pi

B4J – RAD development tool for cross platform desktop, server and IoT solutions

B4J is a 100% free programming tool, similar to B4A that generates desktop, server and web applications.

www.b4x.com

Recommended: OpenJDK 11 + OpenJFX 11

 

[micro]

it looks like you don't have JFX installed on your pi

B4J – RAD development tool for cross platform desktop, server and IoT solutions

B4J is a 100% free programming tool, similar to B4A that generates desktop, server and web applications.

www.b4x.com

Recommended: OpenJDK 11 + OpenJFX 11

Maybe I have explained myself wrongly
Of course there is javafx, the program has been working for a long time on the raspberry the problem is on the last modification as explained in the thread
If you read the thread carefully you will understand
Thanks