Building openjfx

[Nir Lisker]

Gradle tells you how to find out what you're doing wrong:

* 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.


In any case, the error message is straightforward: "Unsupported class file
major version 69" means that the corresponding Java version (25) is
unsupported in the Gradle version you're using. You can create a file
inside your gradle home directory (.gradle) called "gradle.properties" and
set the org.gradle.java.home property to the path of a previous Java
version if you don't want to change your global env var.

On Tue, Oct 14, 2025 at 9:41 AM Michael Zucchi <notzed at gmail.com> wrote:

>
> Orion,
>
> I believe you have to use openjdk 24 as gradle 8.14.x doesn't support 25.
>
> I also had to add -Dorg.gradle.java.home=/correct/path as it insisted on
> using the wrong version of many installed locally.
>
> Otherwise I found it pretty trivial to build, good luck.
>
>   Z
>
>
> On 14/10/25 10:52, 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?
> >
>
>
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