JavaFX: Cannot open display problem

Question

I want to create some GUI for Raspberry Pi 1 B. So I found JavaFX is best for my purpose. Installed it following this tutorial : oracle.com/webfolder/technetwork/tutorials/obe/java/RaspberryPiFX/raspberryfx.html

Created Basic JavaFX Application-Hello World. Copied BasicFX.jar to pi and ran using ::

sudo java -jar BasicFX.jar But it showed this error :: error: could not find or load main class java

After searching for solution , I found this : stackoverflow.com/questions/38359076/how-can-i-get-javafx-working-on-raspberry-pi-3 . But Running it again showing this error now ::

Cannot open display
Exception in Application start method
java.lang.reflect.InvocationTargetException
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
 at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
 at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
 at com.sun.javafx.application.LauncherImpl.lambda$launchApplication156ドル(LauncherImpl.java:182)
 at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ExceptionInInitializerError
 at javafx.scene.Node.reapplyCss(Node.java:8983)
 at javafx.scene.Node.impl_reapplyCSS(Node.java:8946)
 at javafx.scene.Node.invalidatedScenes(Node.java:854)
 at javafx.scene.Node.setScenes(Node.java:919)
 at javafx.scene.Scene9ドル.invalidated(Scene.java:1119)
 at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:111)
 at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
 at javafx.scene.Scene.setRoot(Scene.java:1072)
 at javafx.scene.Scene.<init>(Scene.java:347)
 at javafx.scene.Scene.<init>(Scene.java:223)
 at basicfx.BasicFX.start(BasicFX.java:37)
 at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1163ドル(LauncherImpl.java:863)
 at com.sun.javafx.application.PlatformImpl.lambda$runAndWait176ドル(PlatformImpl.java:326)
 at com.sun.javafx.application.PlatformImpl.lambda$null174ドル(PlatformImpl.java:295)
 at java.security.AccessController.doPrivileged(Native Method)
 at com.sun.javafx.application.PlatformImpl.lambda$runLater175ドル(PlatformImpl.java:294)
 at com.sun.glass.ui.monocle.RunnableProcessor.runLoop(RunnableProcessor.java:93)
 at com.sun.glass.ui.monocle.RunnableProcessor.run(RunnableProcessor.java:52)
 ... 1 more
Caused by: java.lang.NullPointerException
 at com.sun.javafx.font.PrismFontLoader.loadFont(PrismFontLoader.java:196)
 at javafx.scene.text.Font.<init>(Font.java:319)
 at javafx.scene.text.Font.getDefault(Font.java:86)
 at javafx.scene.CssStyleHelper.<clinit>(CssStyleHelper.java:1528)
 ... 19 more
Exception running application basicfx.BasicFX

Answer 1

I have installed Raspbian Stretch Lite. So,I needed to install X11 Xwindows.

I installed minimal packages, enough to run JavaFX ::

sudo apt install xorg libgtk2.0-0

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