When trying to configure the project using Java 21 I'm getting the error:
Unsupported Java. Your build is currently configured to use Java 21 and Gradle 8.3.
Unfortunately, there is no information in official documentation for now: https://docs.gradle.org/current/userguide/compatibility.html
A Java version between 8 and 20 is required to execute Gradle. Java 21 and later versions are not yet supported.
Starting from which version does Gradle support Java 21?
Update: Gradle 9.0.0 requires Java 17+ to run, uses Kotlin 2 and Groovy 4, and adopts Semantic Versioning (SemVer) with version numbers in the format MAJOR.MINOR.PATCH.
Requiring Java 17+ is a breaking change from previous versions, which supported Java 8+.
See Release Notes, What’s New, and Upgrading to Gradle 9.0.0.
See Compatibility Matrix in the fine manual.
Gradle 8.7 supports Java 22 for compiling, testing, and running JVM-based projects. See Gradle Release Notes and Gradle User Manual.
But Gradle 8.7 cannot run itself on Java 22. Gradle releases tend to lag behind Java releases because Gradle depends on Groovy and Kotlin which must both be updated first. The workaround is to install both Java 21 and Java 22. Run Gradle 8.7 on Java 21, while letting Gradle manage your Java 22 project. To do this in IntelliJ, see my Answer.
See related Question, Gradle 8.7 cannot find installed JDK 22 in IntelliJ.
Tip: For managing installations of Java versions on Unix-oriented platforms (macOS, Linux, etc.), I like to use SDKMAN!.
For full Java 21 support, you can use Gradle 8.5. The release notes say:
With this release, Gradle now fully supports compiling, testing and running on Java 21.
If migrating from older Gradle, see What's new in Gradle 8.0.
Gradle 8.5 is now GA and it has full Java 21 support.
You can update your wrapper config file to:
distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
And if you are using idea, you can go Settings | Build, Execution, Deployment | Build Tools | Gradle and change the Gradle JVM to 21.
As mentioned in other answers, Gradle 8.4 supports building Java 21 projects.
As to how to do that:
Install JDK21 on the machine and tell Gradle to use it as its toolchain.
In your Gradle build file (build.gradle or build.gradle.kts):
java {
toolchain {
languageVersion = JavaLanguageVersion.of(21)
}
}
Gradle should find your JDK21 installation automatically.
Install a JDK version below 21 and use it to execute your Gradle tasks:
Either point your JAVA_HOME variable to this lower version JDK installation, or point the property org.gradle.java.home (gradle.properties) to it. If you use IntelliJ, you should instead point the setting 'Gradle JVM' to this JDK.
To upgrade Gradle to 8.4, either download it from gradle.org and install it manually or (preferably) update your gradle-wrapper.properties file with distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-bin.zip.
Explanation: by default, Gradle uses the same JDK that it runs on to compile your sources. Obviously that is not going to work when you need to compile Java 21 code but the latest Gradle release doesn't run on Java 21 yet.
So you let Gradle run on a lower version (either your environment default - what is returned by java --version, or some other JDK as specified for instance in the Gradle JVM option of IntelliJ or by setting org.gradle.java.home in gradle.properties) but you instruct it to use a 21 JDK for building your project (compilation, javadoc generation, etc.).
Edit: Despite claims to the contrary by Gradle, it seems that (at least for simple projects) Gradle 8.4 is already able to run on Java 21.
If you run into problems use the steps above, but it should be enough to simply run gradle build/gradlew build with JDK21 and Gradle 8.4 (so step 2 can be skipped).
Starting with Gradle 8.5 it should be officially supported to run Gradle directly on JDK21.
Gradle Version 8.4 allows you to build with Java 21. Gradle 8.4 itself however can't run on Java 21. The next Version 8.5 is able to run on Java 21.
Full Java 21 support
Gradle 8.4 supported compiling and testing with Java 21 using Java toolchains, but running Gradle itself on Java 21 was not yet supported.
With this release, Gradle now fully supports compiling, testing and running on Java 21.
Java 22:
Gradle 8.7 can build for Java 22, but needs Java 21 or older to run.
I believe there is new release of gradle for JDK 21:
https://docs.gradle.org/8.4-rc-1/release-notes.html#kotlin-dsl-improvements
gradle 8.4-rc-1
I was able to install, but I'm still having java errors with classpath issues.
If you are using Intellij, until v8.5 is G.A, you need to set Gradle JVM to a JVM version lower than Java 21, example Java 20:
Settings > Build, Execution, Deployment > Build Tools > Gradle:
Looking at the Gradle compatability matrix, it will work from Gradle version 8.5.
Java version Support for toolchains Support for running Gradle … … … 20 8.1 8.3 21 8.4 8.5 … … …
java { toolchain { languageVersion = 21 } }