Raise Java baseline & ensure FBA runs cleanly on Java 22 (deprecate Java 8)

[xts-Michi]

Issue: Raise Java baseline to 17 & ensure FBA runs cleanly on JDK 22+

Summary

SBSCL currently targets Java 8. This issue proposes to raise the minimum required Java version to 17 (LTS) and to verify FBA runs cleanly on JDK 22+. This removes Java 8 support and the related maintenance burden.

Motivation

• Modern JDKs (17/22+) provide security, performance, and tooling improvements.
• Avoid brittle JAXP conflicts on newer JDKs (e.g., AbstractMethodError in Log4j2 XML config when legacy XML parsers shadow the JDK’s).
• Simplify build, CI, and contributor experience.

Proposed Change

• Set baseline to Java 17: update maven-compiler-plugin to <release>17</release>.
• CI matrix: test on JDK 17 (LTS) and JDK 22+.
• Classpath hardening: remove/avoid legacy XML parser stack (xercesImpl, xml-apis, xalan) so the JDK’s JAXP is used.
• Docs: update README.md / INSTALL.md to state Java 17+ is required.

Observed Behavior (current)

• On JDK 22, early failures can occur in Log4j2 XML config if legacy XML parsers take precedence over the JDK’s, leading to AbstractMethodError.
  Removing those legacy parsers allows the FBA path to initialize and solve as expected.

Impact / Compatibility

• Breaking change: downstream users must run on Java 17+.
• Build and runtime get simpler; fewer surprises on modern JDKs.

[dyrpsf]

Hi @xts-Michi

I’d like to work on this issue.

Planned steps:

1. Update the Maven compiler configuration to target Java 17 (using <release>17</release>).
2. Adjust any Maven plugins/build settings that still assume Java 8.
3. Remove or replace legacy XML parser dependencies (e.g. xercesImpl, xml-apis, xalan) so that the JDK’s built‑in JAXP stack is used.
4. Verify that FBA and the rest of SBSCL build and run cleanly on JDK 17 and JDK 22+ (locally, and then in CI if available).
5. Update README / installation docs to state Java 17+ is required.

I’m still relatively new to the codebase, so feedback on the approach or any constraints you have (e.g. specific JDK versions to test, dependencies that must be kept) would be very welcome.

[dyrpsf]

Hi @xts-Michi @matthiaskoenig @draeger

I’ve opened a pull request for this: #97

Summary of changes:

• Java baseline: Updated the build to target Java 17 by
  • Setting <jdk.version> to 17 in pom.xml.
  • Upgrading maven-compiler-plugin to 3.11.0 and using <release>17</release>.
• XML parser stack: Removed legacy JAXP implementations brought in via jlibsedml by adding exclusions for:
  • xerces:xercesImpl
  • xml-apis:xml-apis
  • xalan:xalan
    so the JDK’s built-in XML stack is used (avoiding the AbstractMethodError on newer JDKs).
• CI: Updated .travis.yml to run the test matrix on OpenJDK 17 and a newer OpenJDK version instead of Java 11.
• Docs: Updated README.md, INSTALL.md, and UserGuidelines.md to state that SBSCL requires Java 17 or newer.
• Verification: mvn test passes locally on my machine using a Java 17+ JDK (JDK 24).

Feedback on the chosen JDK versions in CI or any additional checks you’d like me to run is very welcome.

[xts-Michi]

Hey @dyrpsf , thank you for your work.
I will look into that as soon as possible and discuss the suggested changes.

[dyrpsf]

@xts-Michi
Thanks for the quick response!
I’m happy to adjust anything you’d like changed or run any additional checks.
Just let me know what you prefer and I’ll update the PR accordingly.