Ah yes, you are running into one of the charming issues with using
gradle: namely, gradle is slow in supporting the latest JDKs.
The easiest way is to use JDK 24.x (e.g., 24.0.2) to both run gradle and
build JavaFX. This is what we do.
If you need to use JDK 25 to build, you will need two JDKs: one to run
gradle (JDK 24 or earlier) and another to use for building. Point
JAVA_HOME to the JDK used to launch gradle and put it in your PATH.
Point JDK_HOME to the JDK 25 that you will use to build JavaFX.
-- Kevin
On 10/13/2025 5:22 PM, Orion Poplawski wrote:
So I'm stepping back to simply try building openjfx with gradlew but I
get:
$ sh gradlew --info build
Initialized native services in: /home/orion/.gradle/native
Initialized jansi services in: /home/orion/.gradle/native
The client will now receive all logging from the daemon (pid: 253483).
The daemon log file:
/home/orion/.gradle/daemon/8.14.2/daemon-253483.out.log
Starting 2nd build in daemon [uptime: 2 mins 22.763 secs, performance:
97%, GC rate: 0.00/s, heap usage: 2% of 512 MiB, non-heap usage: 9% of
384 MiB]
Using 6 worker leases.
Now considering [/home/orion/openjfx-25/jfx25u-25-29] as hierarchies
to watch
Now considering [/home/orion/openjfx-25/jfx25u-25-29/buildSrc,
/home/orion/openjfx-25/jfx25u-25-29] as hierarchies to watch
Watching the file system is configured to be enabled if available
File system watching is active
Starting Build
Caching disabled for Groovy DSL script compilation (settings) because:
Build cache is disabled
Not worth caching.
Compiling settings file
'/home/orion/openjfx-25/jfx25u-25-29/settings.gradle' using
BuildScriptTransformer.
FAILURE: Build failed with an exception.
* What went wrong:
BUG! exception in phase 'semantic analysis' in source unit
'_BuildScript_' Unsupported class file major version 69
> Unsupported class file major version 69
* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --debug option to get more log output.
> Run with --scan to get full insights.
> Get more help at https://help.gradle.org.
BUILD FAILED in 466ms
$ java --version
openjdk 25 2025-09-16
OpenJDK Runtime Environment (Red_Hat-25.0.0.0.36-1) (build 25+36)
OpenJDK 64-Bit Server VM (Red_Hat-25.0.0.0.36-1) (build 25+36, mixed
mode, sharing)
What am I doing wrong?
