Run attached code and get exception:

Exception in Application start method
Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
        at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:378)
        at com.sun.javafx.application.LauncherImpl.access$000(LauncherImpl.java:27)
        at com.sun.javafx.application.LauncherImpl$1.run(LauncherImpl.java:97)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.IllegalStateException: The window has already been closed
        at com.sun.glass.ui.Window.checkNotClosed(Window.java:202)
        at com.sun.glass.ui.Window.setEnabled(Window.java:641)
        at com.sun.javafx.tk.quantum.WindowStage.setPlatformEnabled(WindowStage.java:546)
        at com.sun.javafx.tk.quantum.WindowStage.setEnabled(WindowStage.java:557)
        at com.sun.javafx.tk.quantum.QuantumToolkit.showFileChooser(QuantumToolkit.java:1365)
        at javafx.stage.FileChooser.showDialog(FileChooser.java:264)
        at javafx.stage.FileChooser.showOpenDialog(FileChooser.java:213)
        at modalitystandaloneclosing.Main.start(Main.java:56)
        at com.sun.javafx.application.LauncherImpl$5.run(LauncherImpl.java:298)
        at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:152)
        at com.sun.javafx.application.PlatformImpl$3.run(PlatformImpl.java:119)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
        at com.sun.glass.ui.win.WinApplication$2$1.run(WinApplication.java:62)
        ... 1 more
Java Result: 1