Bug ID: JDK-8298104 NPE on synchronizeSceneNodes()

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A DESCRIPTION OF THE PROBLEM :
A null pointer exception occurs on the ScenePulseListener when iterating through the dirty node list:

for (int i = 0 ; i < dirtyNodesSize; ++i) {
  Node node = dirtyNodes[i];
  dirtyNodes[i] = null;
  if (node.getScene() == Scene.this) node.syncPeer();
}

A null check is needed on the node before calling node.getScene()

Note: this bug was previously reported on JDK 8 and marked as fixed:
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8095034

The latest code does not preform this check.

The original bug mentions that this is a symptom and not a cause, but there does not appear to be any way to determine the cause in this case.

In some cases, this happens so frequently that the application locks up and the end user needs to restart.  I have downloaded the JFX project from git hub and manually patched which solves the problem.

A one line fix would be greatly appreciated (and/or an explanation of what the cause could be).


CUSTOMER SUBMITTED WORKAROUND :
I have manually downloaded the GITHub project and added the NPE check.  This fixes the issue.

FREQUENCY : occasionally

A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jfx/pull/1123 Date: 2023-05-03 11:46:50 +0000

09-07-2024

This seems like a rare corner case scenario. Adding a null check blindly would be like just avoiding the side effect. Cause could be in application or in JavaFX, but hard to say anything without a test program or the scenario when this issue occurs.

02-01-2023

Relates to JDK-8095034

05-12-2022

Relates :	JDK-8303736 - Incomplete mechanism for preventing changing JavaFX component from non-FX thread
Relates :	JDK-8095034 - NullPointerException at javafx.scene.Scene$ScenePulseListener.synchronizeSceneNodes