Build errors on fedora 43

[inuyasha82]

I think they are most likely related to local configuration, i would appreciate any help.

I'm trying to build locally your project, using make dev and get the following error messages:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  11:51 min (Wall Clock)
[INFO] Finished at: 2026-05-12T15:38:03+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.15.0:compile (default-compile) on project sandbox-functional-converter-core: Fatal error compiling: error: release version 21 not supported -> [Help 1]
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.15.0:compile (default-compile) on project sandbox-ast-api: Fatal error compiling: error: release version 21 not supported -> [Help 1]
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.15.0:compile (default-compile) on project sandbox_common_core: Fatal error compiling: error: release version 21 not supported -> [Help 1]
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.15.0:compile (default-compile) on project sandbox-jgit-storage-hibernate: Fatal error compiling: error: release version 21 not supported -> [Help 1]
[ERROR] Failed to execute goal org.eclipse.tycho:tycho-compiler-plugin:5.0.2:compile (default-compile) on project sandbox_css_cleanup: Fatal error compiling: Cannot invoke "java.nio.file.FileSystem.getPath(String, String[])" because "this.fs" is null -> [Help 1]
[ERROR] Failed to execute goal org.eclipse.tycho:tycho-compiler-plugin:5.0.2:compile (default-compile) on project sandbox_cleanup_application: Fatal error compiling: Cannot invoke "java.nio.file.FileSystem.getPath(String, String[])" because "this.fs" is null -> [Help 1]
[ERROR] Failed to execute goal org.eclipse.tycho:tycho-compiler-plugin:5.0.2:compile (default-compile) on project sandbox_test_commons: Fatal error compiling: Cannot invoke "java.nio.file.FileSystem.getPath(String, String[])" because "this.fs" is null -> [Help 1]
[ERROR] Failed to execute goal org.eclipse.tycho:tycho-compiler-plugin:5.0.2:compile (default-compile) on project sandbox_extra_search: Fatal error compiling: Cannot invoke "java.nio.file.FileSystem.getPath(String, String[])" because "this.fs" is null -> [Help 1]
[ERROR] 

I'm using java 25.

gualandri:sandbox$ java --version
openjdk 25.0.2 2026-01-20
OpenJDK Runtime Environment (Red_Hat-25.0.2.0.10-3) (build 25.0.2+10)
OpenJDK 64-Bit Server VM (Red_Hat-25.0.2.0.10-3) (build 25.0.2+10, mixed mode, sharing)

And mvn:

gualandri:sandbox$ mvn --version
Apache Maven 3.9.11 (3e54c93a704957b63ee3494413a2b544fd3d825b)
Maven home: /home/gualandri/Tools/apache-maven-3.9.11
Java version: 25.0.2, vendor: Red Hat, Inc., runtime: /usr/lib/jvm/java-25-openjdk
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "6.19.12-200.fc43.x86_64", arch: "amd64", family: "unix"

[carstenartur]

Hi @inuyasha82, thanks for the detailed report — both errors are caused by the same root issue: you're building with JDK 25, but this project targets Java 21.

1. release version 21 not supported (maven-compiler-plugin)
Even though mvn -version reports JDK 25, the compiler-plugin process is most likely picking up an older JDK on your system (via JAVA_HOME, a Maven toolchain, or PATH). JDK 25 itself can compile --release 21, but if any older JDK gets forked, this is exactly the message you'll see.

2. Cannot invoke "java.nio.file.FileSystem.getPath(...)" because "this.fs" is null (tycho-compiler-plugin 5.0.2)
This is a known incompatibility between Tycho 5.0.2's embedded ECJ and very new JDKs (24/25). The internal JrtFileSystemProvider lookup returns null, which causes the NPE. Tycho 5.0.2 is not certified for JDK 25.

Fix — build with JDK 21:

sudo dnf install java-21-openjdk-devel
export JAVA_HOME=/usr/lib/jvm/java-21-openjdk
export PATH=$JAVA_HOME/bin:$PATH
mvn -version   # should now show 21
make dev

That should resolve both error classes. Let me know if it still fails after switching JDKs.