Setup Jena 6 development

[afs]

GitHub issue resolved #3528

Includes some final clearing up from jena-iri and switching to having only jena-iri3986.

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• Tests are included.
• Commits have been squashed to remove intermediate development commit messages.
• Key commit messages start with the issue number (GH-xxxx)

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[afs]

@Aklakan -- I hope that there are no changes that impact any of your current PRs.

The changes are POMs, deal with warnings from jena 21, especially new URL() used in tests, some remaining uses of jena-iri were lurking. Object.finalize is now deprected for removal. In geosparql, the override of TaskThread.isTerminated no longer is legal.

Subject to more testing, I think the switch-over is ready.

[Aklakan]

Thanks for the heads up @afs - is there anything from my side blocking your PR? If not I would just rebase after your merge into main and fix any conflicts.

[afs]

is there anything from my side blocking your PR? If not I would just rebase after your merge into main and fix any conflicts.

No - nothing blocking.

I've been merging it into various branches I have with no problems for Java.

Changes to POMs from simplifying the test dependencies in parallel to changing the version caused merge conflicits but nothing complicated.

The less change at the switchover point the better, so that further work (e.g. deprecation removals) can be done in isolated steps.