Fixes double check locking by adding the `volatile` keyword. During normal operation, the access seems to happen from two threads:
Thread[#29,QuantumRenderer-0,5,main] Thread[#34,JavaFX Application Thread,5,main] On one hand, this access is likely to be mutually exclusive, on the other hand, javafx does allow the nodes to be created in a background thread, and it might be possible to invoke, for example, `GlyphLayout.breakRuns()` from a background thread. --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - volatile Changes: https://git.openjdk.org/jfx/pull/2205/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2205&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8387684 Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod Patch: https://git.openjdk.org/jfx/pull/2205.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/2205/head:pull/2205 PR: https://git.openjdk.org/jfx/pull/2205
