[External] : Re: ConcurrentModificationException when calling stage.show()

Kevin Rushforth kevin.rushforth at oracle.com
Thu Sep 8 12:26:28 UTC 2022


Presuming that you aren't calling initialize directly from some other 
thread, and aren't concurrently accessing the menu from some other 
thread, I agree that adding a runLater shouldn't be needed. So yes, this 
does seem like our bug. Can you file a bug report at 
https://bugreport.java.com/ with a complete standalone test case?

-- Kevin

On 9/7/2022 11:57 PM, Daniel Peintner wrote:
> Hi Kevin, all,
>
> I investigated further and I think I found the problem (or at least a 
> solution).
>
> In my application I use FXML+Controller approach.
>
> The issue I described arises if in controller.initialize(...).
> I update the menu-items of a menu. In my case, the menu list is empty 
> in FXML and while initializing I update the menu with the "recently" 
> opened files so that people can restart their work with files they 
> opened before.
>
> The solution that works in my case is to wrap these menu updates in 
> Platform.runLater() even though I think this should not be needed. Am 
> I right?
>
> public class MyLayoutController extends BorderPane implements 
> Initializable {
>     @Override
>     public void initialize(URL location, ResourceBundle resources) {
>         // updating the menu updates within runLater() does not cause 
> ConcurrentModificationException
>         Platform.runLater(() -> {
>            // anyhow, I think this should not be needed
>            this.menu.getItems().add(new MenuItem("A"));
>            this.menu.getItems().add(new MenuItem("B"));
>            this.menu.getItems().add(new MenuItem("C"));
>         });
>     }
> }
>
> Is this sufficient to create a bug report?
>
> Thanks,
>
> -- Daniel
>
>
>
>
> On Mon, Sep 5, 2022 at 7:47 PM Kevin Rushforth 
> <kevin.rushforth at oracle.com> wrote:
>
>     I suspect a JavaFX bug, unless there some other thread not shown
>     in your
>     stack trace that is modifying any object in the now-live scene graph.
>
>     -- Kevin
>
>
>     On 9/5/2022 6:34 AM, Daniel Peintner wrote:
>     > All,
>     >
>     > I have a strange issue popping up once in a while.
>     > I have an application (FXML+ Controller) that has a "new" button
>     > opening a new window. In 99% percent of the cases this works
>     just fine.
>     >
>     > In some rare cases though, stage.show() fails due to a
>     > ConcurrentModificationException. Since this issue does not
>     happen in
>     > my code but rather in JavaFX code I wanted to ask whether there
>     is a
>     > specific prerequisite I am not aware of or whether this is a bug in
>     > JavaFX.
>     >
>     > Attached the stack trace. Unfortunately I am not able to create a
>     > reproducible example that fails always.
>     >
>     > I am grateful for any tip.
>     >
>     > Thanks,
>     >
>     > -- Daniel
>     >
>     >
>     > Exception in thread "JavaFX Application Thread"
>     > java.lang.RuntimeException:
>     java.lang.reflect.InvocationTargetException
>     > at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1857)
>     > at
>     >
>     javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1724)
>     > at
>     >
>     com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
>     > at
>     >
>     com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
>     > at
>     >
>     com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
>     > at
>     >
>     com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
>     > at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
>     > at javafx.event.Event.fireEvent(Event.java:198)
>     > at javafx.scene.Node.fireEvent(Node.java:8797)
>     > at javafx.scene.control.Button.fire(Button.java:203)
>     > at
>     >
>     com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:208)
>     > at
>     >
>     com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
>     > at
>     >
>     com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:247)
>     > at
>     >
>     com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
>     > at
>     >
>     com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
>     > at
>     >
>     com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
>     > at
>     >
>     com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at
>     >
>     com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
>     > at
>     >
>     com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
>     > at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
>     > at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
>     > at javafx.event.Event.fireEvent(Event.java:198)
>     > at javafx.scene.Scene$MouseHandler.process(Scene.java:3881)
>     > at javafx.scene.Scene.processMouseEvent(Scene.java:1874)
>     > at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2607)
>     > at
>     >
>     com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:411)
>     > at
>     >
>     com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:301)
>     > at
>     >
>     java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
>     > at
>     >
>     com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:450)
>     > at
>     >
>     com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:424)
>     > at
>     >
>     com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:449)
>     > at com.sun.glass.ui.View.handleMouseEvent(View.java:551)
>     > at com.sun.glass.ui.View.notifyMouse(View.java:937)
>     > at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
>     > at
>     >
>     com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
>     > at java.base/java.lang.Thread.run(Thread.java:833)
>     > Caused by: java.lang.reflect.InvocationTargetException
>     > at
>     >
>     java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
>
>     > Method)
>     > at
>     >
>     java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
>     > at
>     >
>     java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>     > at java.base/java.lang.reflect.Method.invoke(Method.java:568)
>     > at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:77)
>     > at
>     >
>     java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native
>
>     > Method)
>     > at
>     >
>     java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
>     > at
>     >
>     java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>     > at java.base/java.lang.reflect.Method.invoke(Method.java:568)
>     > at com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:275)
>     > at com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:84)
>     > at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1854)
>     > ... 50 more
>     > Caused by: java.util.ConcurrentModificationException
>     > at
>     >
>     java.base/java.util.AbstractList$Itr.checkForComodification(AbstractList.java:399)
>     > at java.base/java.util.AbstractList$Itr.next(AbstractList.java:368)
>     > at
>     >
>     javafx.scene.control.skin.MenuBarSkin.updateActionListeners(MenuBarSkin.java:810)
>     > at
>     >
>     javafx.scene.control.skin.MenuBarSkin.updateActionListeners(MenuBarSkin.java:811)
>     > at
>     javafx.scene.control.skin.MenuBarSkin.rebuildUI(MenuBarSkin.java:1017)
>     > at
>     javafx.scene.control.skin.MenuBarSkin.<init>(MenuBarSkin.java:356)
>     > at javafx.scene.control.MenuBar.createDefaultSkin(MenuBar.java:202)
>     > at javafx.scene.control.Control.doProcessCSS(Control.java:899)
>     > at javafx.scene.control.Control$1.doProcessCSS(Control.java:89)
>     > at
>     >
>     com.sun.javafx.scene.control.ControlHelper.processCSSImpl(ControlHelper.java:67)
>     > at com.sun.javafx.scene.NodeHelper.processCSS(NodeHelper.java:146)
>     > at javafx.scene.Parent.doProcessCSS(Parent.java:1400)
>     > at javafx.scene.Parent$1.doProcessCSS(Parent.java:125)
>     > at
>     com.sun.javafx.scene.ParentHelper.processCSSImpl(ParentHelper.java:98)
>     > at com.sun.javafx.scene.NodeHelper.processCSS(NodeHelper.java:146)
>     > at javafx.scene.Parent.doProcessCSS(Parent.java:1400)
>     > at javafx.scene.Parent$1.doProcessCSS(Parent.java:125)
>     > at
>     com.sun.javafx.scene.ParentHelper.processCSSImpl(ParentHelper.java:98)
>     > at com.sun.javafx.scene.NodeHelper.processCSS(NodeHelper.java:146)
>     > at javafx.scene.Parent.doProcessCSS(Parent.java:1400)
>     > at javafx.scene.Parent$1.doProcessCSS(Parent.java:125)
>     > at
>     com.sun.javafx.scene.ParentHelper.processCSSImpl(ParentHelper.java:98)
>     > at com.sun.javafx.scene.NodeHelper.processCSS(NodeHelper.java:146)
>     > at javafx.scene.Node.processCSS(Node.java:9477)
>     > at javafx.scene.Scene.doCSSPass(Scene.java:572)
>     > at javafx.scene.Scene.preferredSize(Scene.java:1770)
>     > at javafx.scene.Scene$2.preferredSize(Scene.java:396)
>     > at
>     com.sun.javafx.scene.SceneHelper.preferredSize(SceneHelper.java:66)
>     > at javafx.stage.Window$12.invalidated(Window.java:1163)
>     > at
>     >
>     javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
>     > at
>     >
>     javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:145)
>     > at javafx.stage.Window.setShowing(Window.java:1239)
>     > at javafx.stage.Window.show(Window.java:1254)
>     > at javafx.stage.Stage.show(Stage.java:277)
>     > at
>     >
>     com.foo.MainLayoutController.openNewWindow(MainLayoutController.java:3851)
>     >
>     >
>     >
>     >
>     >
>     >
>
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