NPE is JavaFX Task

[Kevin Rushforth]

This is due to a concurrency bug in CSS StyleManager class:

https://javafx-jira.kenai.com/browse/RT-40417

It is currently not thread-safe, but it needs to be given that controls 
may be constructed on arbitrary threads.

I plan to start working on this bug later this week and will use your 
example as another test case.

-- Kevin


Peter Penzov wrote:
> Update: Same result with this code:
>
> public void addNewTab(DynamicTreeNodeModel nodeModel)
>     {
>         final Tab tab = new Tab();
>
>         final ProgressBar progressBar = new ProgressBar();
>         final Task<BorderPane> loadDataTask = new Task<BorderPane>()
>         {
>             @Override
>             public BorderPane call() throws Exception
>             {
>                 Content content = new Content(primaryStage,
> treeView.getSelectionModel().getSelectedItem());
>                 return content.initContentData();
>             }
>         };
>         tab.setContent(progressBar);
>         loadDataTask.setOnSucceeded(new EventHandler<WorkerStateEvent>()
>         {
>             @Override
>             public void handle(WorkerStateEvent event)
>             {
>                 BorderPane data = loadDataTask.getValue();
>                 tab.setContent(data);
>             }
>         });
>         final Thread thread = new Thread(loadDataTask);
>         thread.setDaemon(true);
>         thread.start();
>
>         newTabLabel = new Label(nodeModel.getName());
>         tab.setStyle("-fx-focus-color: transparent;");  // Remove the blue
> dashed label from label
>         tab.setGraphic(newTabLabel);
>         tab.setContextMenu(makeTabContextMenu(tab, newTabLabel, tabPane));
>
>         tabPane.getTabs().add(0, tab);
>         tabPane.getSelectionModel().select(tab);
>         tabPane.setTabClosingPolicy(TabPane.TabClosingPolicy.ALL_TABS);
>     }
>
> On Wed, May 27, 2015 at 12:56 PM, Peter Penzov <peter.penzov at gmail.com>
> wrote:
>
>   
>> Hi All,
>>     I have a question about a issue that I have with JavaFX Task. I'm
>> using the code from this example to display progress bar in TabPane when I
>> click on TreeView Node:
>>
>> http://stackoverflow.com/questions/22803845/loading-logic-for-javafx-task
>>
>> For some reason when I click multiple times on the node I get this
>> exception:
>>
>>
>> Exception in thread "JavaFX Application Thread"
>> java.lang.NullPointerException
>>         at com.sun.javafx.css.StyleManager.findMatchingStyles(Unknown
>> Source)
>>         at javafx.scene.CssStyleHelper.createStyleHelper(Unknown Source)
>>         at javafx.scene.Node.reapplyCss(Unknown Source)
>>         at javafx.scene.Node.impl_reapplyCSS(Unknown Source)
>>         at javafx.scene.Node.invalidatedScenes(Unknown Source)
>>         at javafx.scene.Node.setScenes(Unknown Source)
>>         at javafx.scene.Parent$1.onChanged(Unknown Source)
>>         at
>> com.sun.javafx.collections.TrackableObservableList.lambda$new$19(Unknown
>> Source)
>>         at
>> com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(Unknown
>> Sourc
>> e)
>>         at
>> com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(Unknown
>> Source)
>>         at javafx.collections.ObservableListBase.fireChange(Unknown Source)
>>         at javafx.collections.ListChangeBuilder.commit(Unknown Source)
>>         at javafx.collections.ListChangeBuilder.endChange(Unknown Source)
>>         at javafx.collections.ObservableListBase.endChange(Unknown Source)
>>         at javafx.collections.ModifiableObservableListBase.add(Unknown
>> Source)
>>         at java.util.AbstractList.add(Unknown Source)
>>         at com.sun.javafx.collections.VetoableListDecorator.add(Unknown
>> Source)
>>         at
>> com.sun.javafx.scene.control.skin.ProgressIndicatorSkin$IndeterminateSpinner.rebuild(Unkn
>> own Source)
>>         at
>> com.sun.javafx.scene.control.skin.ProgressIndicatorSkin$IndeterminateSpinner.access$400(U
>> nknown Source)
>>         at
>> com.sun.javafx.scene.control.skin.ProgressIndicatorSkin$2.invalidated(Unknown
>> Source)
>>         at javafx.beans.property.IntegerPropertyBase.markInvalid(Unknown
>> Source)
>>         at javafx.beans.property.IntegerPropertyBase.set(Unknown Source)
>>         at javafx.css.StyleableIntegerProperty.set(Unknown Source)
>>         at javafx.beans.property.IntegerProperty.setValue(Unknown Source)
>>         at javafx.css.StyleableIntegerProperty.applyStyle(Unknown Source)
>>         at javafx.css.StyleableIntegerProperty.applyStyle(Unknown Source)
>>         at javafx.scene.CssStyleHelper.transitionToState(Unknown Source)
>>         at javafx.scene.Node.impl_processCSS(Unknown Source)
>>         at javafx.scene.Parent.impl_processCSS(Unknown Source)
>>         at javafx.scene.control.Control.impl_processCSS(Unknown Source)
>>         at javafx.scene.Parent.impl_processCSS(Unknown Source)
>>         at javafx.scene.Parent.impl_processCSS(Unknown Source)
>>         at javafx.scene.Node.processCSS(Unknown Source)
>>         at javafx.scene.Node.processCSS(Unknown Source)
>>         at javafx.scene.Node.processCSS(Unknown Source)
>>         at javafx.scene.Node.processCSS(Unknown Source)
>>         at javafx.scene.Node.processCSS(Unknown Source)
>>         at javafx.scene.Node.processCSS(Unknown Source)
>>         at javafx.scene.Scene.doCSSPass(Unknown Source)
>>         at javafx.scene.Scene.access$3600(Unknown Source)
>>         at javafx.scene.Scene$ScenePulseListener.pulse(Unknown Source)
>>         at com.sun.javafx.tk.Toolkit.lambda$runPulse$31(Unknown Source)
>>         at java.security.AccessController.doPrivileged(Native Method)
>>         at com.sun.javafx.tk.Toolkit.runPulse(Unknown Source)
>>         at com.sun.javafx.tk.Toolkit.firePulse(Unknown Source)
>>         at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
>>         at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
>>         at
>> com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$401(Unknown
>> Source)
>>         at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown
>> Source)
>>         at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
>>         at com.sun.glass.ui.win.WinApplication.lambda$null$146(Unknown
>> Source)
>>         at java.lang.Thread.run(Unknown Source)
>>
>>
>> Can you advice me is this JavaFX issue or the code that I'm using is
>> incorrect?
>>
>> BR,
>> Peter
>>
>> ref
>> http://stackoverflow.com/questions/22803845/loading-logic-for-javafx-task
>>
>>