Maven "error: release version 17 not supported" - Fix JDK in CI

javac rejected the requested --release because the JDK compiling your code is older than that language level. A JDK 11 cannot emit release 17 - it has no knowledge of that version.

What this error means

Compilation aborts with error: release version 17 not supported. The number is the maven.compiler.release your POM requests; the JDK actually running is older than it.

mvn output

[ERROR] Failed to execute goal
org.apache.maven.plugins:maven-compiler-plugin:3.13.0:compile (default-compile)
on project app: Compilation failure
[ERROR] error: release version 17 not supported

Common causes

Runner JDK older than maven.compiler.release

CI defaulted to an older JDK (e.g. 11) while the POM sets <maven.compiler.release>17</maven.compiler.release>. The compiler does not support a release newer than itself.

JAVA_HOME resolves to the wrong JDK

Multiple JDKs are installed and JAVA_HOME (or PATH) points at the older one, so Maven compiles with it regardless of intent.

How to fix it

Provision the matching JDK

Set up the JDK your release targets and verify Maven uses it.

.github/workflows/ci.yml

- uses: actions/setup-java@v4
  with:
    distribution: temurin
    java-version: '17'
- run: mvn -B -version

Lower the release to fit the JDK

If you cannot upgrade, set the release no higher than the running JDK.

pom.xml

<properties>
  <maven.compiler.release>11</maven.compiler.release>
</properties>

How to prevent it

Pin the JDK with setup-java, assert it with mvn -version, and keep maven.compiler.release no higher than the provisioned JDK.