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 <[email protected]> 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? > > > >
