A DESCRIPTION OF THE PROBLEM :
Starting with release 21-ea+17 the following error causes UI tests to fail:

java.lang.AbstractMethodError: Receiver class com.sun.glass.ui.monocle.MonocleWindow does not define or inherit an implementation of the resolved method 'abstract void _updateViewSize(long)' of abstract class com.sun.glass.ui.Window.
javafx.graphics@21-ea/com.sun.glass.ui.Window.setView(Window.java:377)
javafx.graphics@21-ea/com.sun.javafx.tk.quantum.WindowStage.lambda$setScene$0(WindowStage.java:271)
javafx.graphics@21-ea/com.sun.javafx.tk.quantum.QuantumToolkit.runWithRenderLock(QuantumToolkit.java:442)
javafx.graphics@21-ea/com.sun.javafx.tk.quantum.WindowStage.setScene(WindowStage.java:270)
javafx.graphics@21-ea/javafx.stage.Window$12.invalidated(Window.java:1162)
javafx.base@21-ea/javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
javafx.base@21-ea/javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:145)
javafx.graphics@21-ea/javafx.stage.Window.setShowing(Window.java:1239)
javafx.graphics@21-ea/javafx.stage.Window.show(Window.java:1254)
javafx.graphics@21-ea/javafx.stage.Stage.show(Stage.java:277)
com.avereon.xenon@1.7-SNAPSHOT/com.avereon.xenon.SplashScreenPane.show(SplashScreenPane.java:97)
com.avereon.xenon@1.7-SNAPSHOT/com.avereon.xenon.Xenon.start(Xenon.java:316)
org.testfx.toolkit.impl.ApplicationServiceImpl.lambda$start$0(ApplicationServiceImpl.java:49)
java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
javafx.graphics@21-ea/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:456)
java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
javafx.graphics@21-ea/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:455)
com.sun.glass.ui.monocle.RunnableProcessor.runLoop(RunnableProcessor.java:92)
com.sun.glass.ui.monocle.RunnableProcessor.run(RunnableProcessor.java:51)
java.base/java.lang.Thread.run(Thread.java:833)

REGRESSION : Last worked in version 20.0.1


FREQUENCY : always