When the program is running, an exception is thrown after a while, but the line of code that generated it is not indicated. After that, the interface stops responding, but another thread calmly continues its work. With that, after the first exception, it begins to repeat constantly. What is the problem?
the code is https://pastebin.com/VBcnBgpv
an exception:
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344) at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(AbstractMasterTimer.java:267) at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:506) at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490) at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319) at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191) at java.lang.Thread.run(Unknown Source) 