Exception in Application start method
java.lang.NullPointerException
        at javafx.scene.chart.PieChart.layoutChartChildren(Unknown Source)
        at javafx.scene.chart.Chart$1.layoutChildren(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Scene.layoutDirtyRoots(Unknown Source)
        at javafx.scene.Scene.doLayoutPass(Unknown Source)
        at javafx.scene.Scene.access$3900(Unknown Source)
        at javafx.scene.Scene$ScenePulseListener.pulse(Unknown Source)
        at com.sun.javafx.tk.Toolkit.firePulse(Unknown Source)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
        at com.sun.javafx.tk.quantum.QuantumToolkit$9.run(Unknown Source)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
        at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
        at com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
        at com.sun.javafx.application.LauncherImpl.access$000(Unknown Source)
        at com.sun.javafx.application.LauncherImpl$1.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
        at javafx.scene.chart.PieChart.layoutChartChildren(Unknown Source)
        at javafx.scene.chart.Chart$1.layoutChildren(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Parent.layout(Unknown Source)
        at javafx.scene.Scene.layoutDirtyRoots(Unknown Source)
        at javafx.scene.Scene.doLayoutPass(Unknown Source)
        at javafx.scene.Scene.preferredSize(Unknown Source)
        at javafx.scene.Scene.impl_preferredSize(Unknown Source)
        at javafx.stage.Window$10.invalidated(Unknown Source)
        at javafx.beans.property.BooleanPropertyBase.markInvalid(Unknown Source)
        at javafx.beans.property.BooleanPropertyBase.set(Unknown Source)
        at javafx.stage.Window.setShowing(Unknown Source)
        at javafx.stage.Window.show(Unknown Source)
        at javafx.stage.Stage.show(Unknown Source)
        at com.oracle.joverflow.ui.FxMain.start(FxMain.java:40)
        at com.sun.javafx.application.LauncherImpl$5.run(Unknown Source)
        at com.sun.javafx.application.PlatformImpl$5.run(Unknown Source)
        at com.sun.javafx.application.PlatformImpl$4.run(Unknown Source)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
        at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
        ... 1 more