at javafx.graphics/com.sun.javafx.sg.prism.NGCanvas$RenderBuf.validate(NGCanvas.java:214)

java.lang.NullPointerException
	at javafx.graphics/com.sun.javafx.sg.prism.NGCanvas$RenderBuf.validate(NGCanvas.java:214)
	at javafx.graphics/com.sun.javafx.sg.prism.NGCanvas.initCanvas(NGCanvas.java:644)
	at javafx.graphics/com.sun.javafx.sg.prism.NGCanvas.renderContent(NGCanvas.java:607)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
	at javafx.graphics/com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.renderForClip(NGNode.java:2313)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.renderClip(NGNode.java:2281)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2066)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
	at javafx.graphics/com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
	at javafx.graphics/com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
	at javafx.graphics/com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.renderForClip(NGNode.java:2313)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.renderRectClip(NGNode.java:2207)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.renderClip(NGNode.java:2233)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2066)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
	at javafx.graphics/com.sun.javafx.sg.prism.NGSubScene.renderContent(NGSubScene.java:218)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
	at javafx.graphics/com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
	at javafx.graphics/com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
	at javafx.graphics/com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
	at javafx.graphics/com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:479)
	at javafx.graphics/com.sun.javafx.tk.quantum.ViewPainter.paintImpl(ViewPainter.java:328)
	at javafx.graphics/com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:91)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305)
	at javafx.graphics/com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at javafx.graphics/com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:125)
	at java.base/java.lang.Thread.run(Thread.java:834)java.lang.NullPointerException
	at jav