in surface ho questi problemi con il codice
	
	
	
	
	
	
	
		
			
			
			
			
			
		
	
	
	
		
	
	
		
	
			
			
			
				B4J ERROR CODE:
			
		
		
		Waiting for debugger to connect...
Program started.
java.lang.NullPointerException
    at com.sun.javafx.sg.prism.NGCanvas$RenderBuf.validate(NGCanvas.java:213)
    at com.sun.javafx.sg.prism.NGCanvas.initCanvas(NGCanvas.java:640)
    at com.sun.javafx.sg.prism.NGCanvas.renderContent(NGCanvas.java:603)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
    at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
    at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
    at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
    at com.sun.javafx.sg.prism.NGNode.renderForClip(NGNode.java:2294)
    at com.sun.javafx.sg.prism.NGNode.renderRectClip(NGNode.java:2188)
    at com.sun.javafx.sg.prism.NGNode.renderClip(NGNode.java:2214)
    at com.sun.javafx.sg.prism.CacheFilter.impl_renderNodeToCache(CacheFilter.java:671)
    at com.sun.javafx.sg.prism.CacheFilter.render(CacheFilter.java:575)
    at com.sun.javafx.sg.prism.NGNode.renderCached(NGNode.java:2358)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2044)
    at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
    at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
    at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
    at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:477)
    at com.sun.javafx.tk.quantum.ViewPainter.paintImpl(ViewPainter.java:330)
    at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:91)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:125)
    at java.lang.Thread.run(Thread.java:748)
java.lang.NullPointerException
    at com.sun.javafx.sg.prism.NGCanvas$RenderBuf.validate(NGCanvas.java:213)
    at com.sun.javafx.sg.prism.NGCanvas.initCanvas(NGCanvas.java:640)
    at com.sun.javafx.sg.prism.NGCanvas.renderForcedContent(NGCanvas.java:624)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.tk.quantum.ViewPainter.paintImpl(ViewPainter.java:332)
    at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:91)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:125)
    at java.lang.Thread.run(Thread.java:748)
java.lang.NullPointerException
    at com.sun.javafx.sg.prism.NGCanvas$RenderBuf.validate(NGCanvas.java:213)
    at com.sun.javafx.sg.prism.NGCanvas.initCanvas(NGCanvas.java:640)
    at com.sun.javafx.sg.prism.NGCanvas.renderForcedContent(NGCanvas.java:624)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.sg.prism.NGGroup.renderForcedContent(NGGroup.java:198)
    at com.sun.javafx.tk.quantum.ViewPainter.paintImpl(ViewPainter.java:332)
    at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:91)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:125)
    at java.lang.Thread.run(Thread.java:748)