Remove Java 8 build and documentation references.

Jody Garnett (GeoCat)

This proposal is for GeoServer 2.23.0.

• Under Discussion
• In Progress
• Completed
• Rejected
• Deferred

While Java 8 LTS support remains available until 2026, many of the components we depend on, and Jakarta migration, require that we move on to Java 11 LTS.

Remove Java 8 from build system, for example the error prone 8 configuration.

Update documentation with installation and production considerations reference to Java 8. This also allows the native JAI / native ImageIO sections to be removed as they use the Java 8 plug-in system which was removed in Java 9. The developers guide can also be updated (rewritten to more generally talk about Java LTS release support).

The Java 11 specific build jobs for main can be removed.

The server status page can remove the checks for native JAI and native ImageIO (as those will no longer be available).

This will also allow Marlin instructions to be dropped (as this is included in recent Java).

This change has the effect of dropping backwards compatibility with Java 8.

Project Steering Committee:

• Alessio Fabiani:
• Andrea Aime: +1 (2.23.0 only)
• Ian Turton: +1 (2.22.0 or 2.23.0)
• Jody Garnett: +1 (2.22.0 or 2.23.0)
• Jukka Rahkonen: +1 (2.23.0 only)
• Kevin Smith: +1
• Simone Giannecchini:
• Torben Barsballe: +1
• Nuno Oliveira: +1

Community support:

• Fernando Mino: +1

• https://github.com/geoserver/geoserver/pull/6137
• https://osgeo-org.atlassian.net/browse/GEOS-10638
• https://sourceforge.net/p/geoserver/mailman/message/37700439/