这有点难以描述...我在滚动窗格内构建了许多画布（20-100个画布）。一开始一切正常，但是在我更改了画布的数量（例如20-> 40-> 80-> 100-> ...等）之后，我在某个时候得到了以下NullPointerException。
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.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.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.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.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.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:323)
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)
我做了一些研究，发现了这个Cannot use large Canvas as ScrollPane。我创建的画布的宽度为1338，高度为326（或54）。我以为可能是通过更改所需的画布数量来增大画布的尺寸，以便出现错误，但这并没有发生。