JavaFx : Error Cannot be ideantified

Question

I have created an application in JavaFx8 which is working fine but sometimes shows an exception as mentioned below. I can not understand why I m getting this kind of exception. Is there any way to track this exception. Or any one familiar with such exception. Kindly help.

java.lang.NullPointerException
    at com.sun.pisces.PiscesRenderer.fillLCDAlphaMask(PiscesRenderer.java:334)
    at com.sun.prism.sw.SWGraphics.drawStringInternal(SWGraphics.java:776)
    at com.sun.prism.sw.SWGraphics.drawString(SWGraphics.java:732)
    at com.sun.javafx.sg.prism.NGText.renderText(NGText.java:319)
    at com.sun.javafx.sg.prism.NGText.renderContent(NGText.java:277)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:412)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:69)
    at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1283)
    at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:237)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:203)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1254)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:412)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:69)
    at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1283)
    at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:237)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:203)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1254)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:412)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:69)
    at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1283)
    at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:237)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:203)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1254)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:412)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:69)
    at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1283)
    at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:237)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:203)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1254)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:412)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:69)
    at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1283)
    at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:237)
    at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:203)
    at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1254)
    at com.sun.javafx.sg.prism.NodeEffectInput.render(NodeEffectInput.java:154)
    at com.sun.javafx.sg.prism.NodeEffectInput.filter(NodeEffectInput.java:84)
    at com.sun.scenario.effect.Merge.filter(Merge.java:161)
    at com.sun.scenario.effect.DelegateEffect.filter(DelegateEffect.java:70)
    at com.sun.scenario.effect.impl.prism.PrEffectHelper.render(PrEffectHelper.java:164)
    at com.sun.javafx.sg.prism.NGNode$EffectFilter.render(NGNode.java:951)
    at com.sun.javafx.sg.prism.NGNode.renderEffect(NGNode.java:701)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:410)
    at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:69)
    at com.sun.javafx.sg.BaseNode.render(BaseNode.java:1283)
    at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:99)
    at com.sun.javafx.tk.quantum.AbstractPainter.paintImpl(AbstractPainter.java:202)
    at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:95)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)
    at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:129)
    at java.lang.Thread.run(Thread.java:724)

Answer 1

Known issue which is fixed in later builds

Your NullPointerException at line 334 of PiscesRendere.java is a known bug that should be fixed if you upgrade to a later JavaFX 8 build.

RT-31384 fx8.0-b96: NullPointerException in fillLCDAlphaMask in sw pipeline

To self-troubleshoot such issues in the future

1. You can test your code using the latest Java 8 distribution (which includes the latest JavaFX distribution).

2. You can check the bug tracker and file the bug if the bug is not present. You will need to provide more info, e.g. your environment, reproduction steps and an executable code sample that reproduces the bug.

3. You can debug the issue yourself based on the JavaFX source code (for example PiscesRenderer.java source is here). Note that you will need to select the correct source tag to match your build.

4. Or you can build and patch JavaFX yourself.