Hi Everyone,
We've also been experiencing this problem over the years. It seems
to be related to JDK-8198577.
Once it goes wrong, each pulse hits the issue repeated meaning it
can never escape. It's rare, but extremely disruptive when it does
occur because the user loses what they've been working on and has
to restart the app.
I've tried really hard to figure out the conditions this happens
in. I don't think it's a multiple thread issue (although for some
people it almost certainly could be triggered that way) because
we've put conditional breakpoints that trigger whenever anything
that could affect dirty children is done off the app thread. We've
got assert Platform.isFXApplicationThread() all over our app to
make sure the threading is happening properly.
What I think is happening is that getChildTransformedBounds which
is being called inside the updateCachedBounds loop, can in some
rare cases, end up triggering a call to updateCachedBounds on the
same node. Basically updateCachedBounds can call itself
recursively. This is a snipped from Parent.java in updateCachedBounds.
// this checks the newly added nodes first, so if dirtyNodes is the
// whole children list, we can end early
for (int i = dirtyNodes.size() - 1; remainingDirtyNodes > 0; --i) {
final Node node = dirtyNodes.get(i);
if (node.boundsChanged) {
// assert node.isVisible();
node.boundsChanged = false;
--remainingDirtyNodes;
tmp = getChildTransformedBounds(node,
BaseTransform.IDENTITY_TRANSFORM, tmp);
In the code above, if this gets called recursively through
getChildTransformedBounds, then node.boundsChanged will change to
false for all the nodes which stops remainingDirtyNodes from being
updated and i eventually goes negative.
We tried to fix the scene graph when this happens by catching the
exception in the Thread.setDefaultUncaughtExceptionHandler but it
didn't work. Maybe Christopher's suggested fix would work, but as
Kevin says "It needs to be tested to ensure that when we get the
AIOOBE that we can recover. It wouldn't solve anything if we catch
and log that exception only to have it fail shortly after because
the scene graph isn't in a good state (I don't know whether that
would be the case, but it's something that needs to be checked)."
Here's how we tried to fix the scene graph when we caught the
error. The "Fixing IOB Issue" log gets hit all the time, but it
doesn't find any problems, and in the next pulse it hits the
problem again with various different stack traces until it settles
on one. In our latest example of the error, it first occurred
during a Platform.runLater and not during the pulse, but then all
subsequent issues happen during the pulse.
protected static void checkSpecialException(Throwable t) {
if (t instanceof IndexOutOfBoundsException) {
fixIndexOutOfBounds(t);
}
}
public static void fixIndexOutOfBounds(Throwable throwable) {
FXUtilities.log(EmbraceDesktop.class,
org.slf4j.event.Level.INFO <http://org.slf4j.event.Level.INFO>,
"Fixing IOB Issue");
try {
Field dirtyChildrenCountField =
Parent.class.getDeclaredField("dirtyChildrenCount");
dirtyChildrenCountField.setAccessible(true);
Field dirtyChildrenField =
Parent.class.getDeclaredField("dirtyChildren");
dirtyChildrenField.setAccessible(true);
Set<Scene> apps = applicationManager.getApplications();
ArrayList<Node> brokenStack = new ArrayList<>();
for (Scene s: apps) {
fixTreeRecursive(dirtyChildrenCountField,
dirtyChildrenField, s.getRoot(), brokenStack);
}
if (brokenStack.size() > 0) {
StringBuilder errorStack = new StringBuilder();
for (Node n: brokenStack) {
errorStack.append(n.getClass().getSimpleName() + " " +
String.join( ",", n.getStyleClass())).append("\n");
}
EmbraceAnalytics.logCrash("Index out of bounds
crash",errorStack.toString(), throwable);
}
}
catch (Throwable t2) {
FXUtilities.log(EmbraceDesktop.class,
org.slf4j.event.Level.ERROR, "Exception while fixing tree", t2);
}
}
protected static boolean fixTreeRecursive(Field
dirtyChildrenCountField, Field dirtyChildrenField, Parent parent,
ArrayList<Node> brokenStack) throws IllegalAccessException {
List<?> dirtyChildren = (List<?>)
dirtyChildrenField.get(parent);
int dirtyChildrenCount = (int)
dirtyChildrenCountField.get(parent);
if (dirtyChildren != null) {
if (dirtyChildrenCount > dirtyChildren.size()) {
FXUtilities.log(EmbraceDesktop.class,
org.slf4j.event.Level.ERROR, "Offending node1 was " +
parent.getClass().getSimpleName());
dirtyChildrenCountField.set(parent,
dirtyChildren.size());
brokenStack.add(parent);
return true;
}
}
else {
if (parent.getChildrenUnmodifiable().size() <
dirtyChildrenCount) {
FXUtilities.log(EmbraceDesktop.class,
org.slf4j.event.Level.ERROR, "Offending node2 was " +
parent.getClass().getSimpleName());
dirtyChildrenCountField.set(parent,
parent.getChildrenUnmodifiable().size());
brokenStack.add(parent);
return true;
}
}
for (Node n: parent.getChildrenUnmodifiable()) {
if (n instanceof Parent) {
boolean error =
fixTreeRecursive(dirtyChildrenCountField, dirtyChildrenField,
(Parent)n, brokenStack);
if (error) {
brokenStack.add(parent);
FXUtilities.log(EmbraceDesktop.class,
org.slf4j.event.Level.ERROR, "Parent was " +
parent.getClass().getSimpleName());
}
return error;
}
}
return false;
}
I think we should we should put the index check potential fix in
and log when it happens. As far as we can tell, if this issue gets
hit, it's catastrophic 100% of the time. The fix might resolve the
issue. It can't really make it any worse. Another thing we should
do is add a check for recursive entry to that method and log when
that occurs. That's (I think) the real issue, and without a stack
trace of that, it's hard to find the root cause.
I don't know if anyone else has experienced this issue and has
insights/workarounds?
Dean
On Mon, Mar 24, 2025 at 5:22 PM Christopher Schnick
<crschn...@xpipe.io> wrote:
Hello,
We encountered an issue after updating our application
implementation to frequently change the visibility of nodes. We
are essentially now running an implementation that very frequently
changes the visibility of various children nodes based on when
they are needed and shown. When the user performs a lot of
actions, the visibility of many nodes will be changed rapidly.
For that, there are many listeners in place that listen for bounds
changes of nodes to recheck whether they need to be made visible
or not. All the visibility changes are queued up, so they are not
immediately done in the listener after any bounds changes of
parents. They are all properly done on the platform thread with
runLater. When this implementation is running on many client
systems, we sometimes receive an error report with an exception
that looks something like this:
java.lang.IndexOutOfBoundsException: Index -1 out of bounds for
length 2
at
java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:100)
at
java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:106)
at
java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:302)
at java.base/java.util.Objects.checkIndex(Objects.java:365)
at java.base/java.util.ArrayList.get(ArrayList.java:428)
at
javafx.base@25-ea/com.sun.javafx.collections.ObservableListWrapper.get(ObservableListWrapper.java:88)
at
javafx.base@25-ea/com.sun.javafx.collections.VetoableListDecorator.get(VetoableListDecorator.java:326)
at
javafx.graphics@25-ea/javafx.scene.Parent.updateCachedBounds(Parent.java:1769)
at
javafx.graphics@25-ea/javafx.scene.Parent.recomputeBounds(Parent.java:1713)
at
javafx.graphics@25-ea/javafx.scene.Parent.doComputeGeomBounds(Parent.java:1566)
at
javafx.graphics@25-ea/javafx.scene.Parent$1.doComputeGeomBounds(Parent.java:116)
at
javafx.graphics@25-ea/com.sun.javafx.scene.ParentHelper.computeGeomBoundsImpl(ParentHelper.java:84)
at
javafx.graphics@25-ea/com.sun.javafx.scene.layout.RegionHelper.superComputeGeomBoundsImpl(RegionHelper.java:78)
at
javafx.graphics@25-ea/com.sun.javafx.scene.layout.RegionHelper.superComputeGeomBounds(RegionHelper.java:62)
at
javafx.graphics@25-ea/javafx.scene.layout.Region.doComputeGeomBounds(Region.java:3301)
at
javafx.graphics@25-ea/javafx.scene.layout.Region$1.doComputeGeomBounds(Region.java:166)
at
javafx.graphics@25-ea/com.sun.javafx.scene.layout.RegionHelper.computeGeomBoundsImpl(RegionHelper.java:89)
at
javafx.graphics@25-ea/com.sun.javafx.scene.NodeHelper.computeGeomBounds(NodeHelper.java:101)
at
javafx.graphics@25-ea/javafx.scene.Node.updateGeomBounds(Node.java:3908)
at
javafx.graphics@25-ea/javafx.scene.Node.getGeomBounds(Node.java:3870)
at
javafx.graphics@25-ea/javafx.scene.Node.getLocalBounds(Node.java:3818)
at
javafx.graphics@25-ea/javafx.scene.Node.updateTxBounds(Node.java:3972)
at
javafx.graphics@25-ea/javafx.scene.Node.getTransformedBounds(Node.java:3764)
at
javafx.graphics@25-ea/javafx.scene.Node.updateBounds(Node.java:828)
at
javafx.graphics@25-ea/javafx.scene.Parent.updateBounds(Parent.java:1900)
at
javafx.graphics@25-ea/javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2670)
at
javafx.graphics@25-ea/com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:380)
at
javafx.graphics@25-ea/com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:401)
at
javafx.graphics@25-ea/com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:592)
at
javafx.graphics@25-ea/com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:572)
at
javafx.graphics@25-ea/com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:565)
at
javafx.graphics@25-ea/com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$6(QuantumToolkit.java:346)
at
javafx.graphics@25-ea/com.sun.glass.ui.InvokeLaterDispatcher$Future.run$$$capture(InvokeLaterDispatcher.java:95)
at
javafx.graphics@25-ea/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java)
The index out of bounds is not always the same, there are various
variations of this. It happens on all operating systems. It seems
like there is a very specific scenario where an index can be out
of bounds. This happens very rarely, like only a few times out of
some hundred application runs, so I tried my best at forcing it to
reproduce.
The following reproducer works most of the time, but it might have
to be run multiple times. I am aware that it eventually results in
a StackOverflow, but that was the best way to force it reliably,
by just continuously spamming visibility changes to eventually
encounter this rare issue. But I want to emphasize that the same
error also occurs naturally when not being forced like this, but
it is just a lot more rare. So the StackOverflow in the reproducer
has nothing to do with this issue, it also happens later on.
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.Region;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.io.IOException;
public class ParentBoundsBugextends Application {
@Override public void start(Stage stage)throws IOException {
Scene scene =new Scene(createContent(),640,480);
stage.setScene(scene);
stage.show();
stage.centerOnScreen();
}
private RegioncreateContent() {
var b1 =new Button("Click me!");
var b2 =new Button("Click me!");
var vbox =new VBox(b1, b2);
b1.boundsInParentProperty().addListener((observable, oldValue,
newValue) -> {
vbox.setVisible(!vbox.isVisible());
});
b2.boundsInParentProperty().addListener((observable, oldValue,
newValue) -> {
vbox.setVisible(!vbox.isVisible());
});
vbox.boundsInParentProperty().addListener((observable, oldValue,
newValue) -> {
vbox.setVisible(!vbox.isVisible());
});
var stack =new StackPane(vbox,new StackPane());
stack.boundsInParentProperty().addListener((observable, oldValue,
newValue) -> {
vbox.setVisible(!vbox.isVisible());
});
return stack;
}
public static void main(String[] args) {
launch();
}
}
It doesn't necessarily have something to do with running the
visibility change directly in the listener, our application does a
runLater to change the visibility state, still with the same
results. To properly debug this, you will have to launch the
reproducer with a bigger stack size like -Xss8m to increase the
chance that it occurs. Then, you can just set a breakpoint at
jdk.internal.util.Preconditions:302, and wait for it to trigger
the OOB eventually.
This problem is currently the biggest JavaFX issue for us as it
breaks the layout and usually requires a restart to fix.
Looking at the bounds calculation code, the list index bounds
check is very optimistic in that it doesn't check any indices and
relies on multiple assumtions to hold. So if it is very difficult
to find the cause, a simple index bounds check for the list access
would also work fine.
Best
Christopher Schnick
