TLS hostname verification failed for hostname: shibboleth.net

[Cantor, Scott]

I think you'd be better off diagnosing why that system is rejecting a valid certificate chain, there's nothing about it that should cause any difficulty on a modern Java new enough to be running the IdP, which I imagine is a given for your use case.

The plugin itself is hosted over http as well as https, but the problem is the property file with the plugin compatibility properties has the URL embedded so that the plugin knows where it lives. I don't know if it's possible to override that location.

Nor do I know the answer to your initial question (try --help as a start?), but I am positive that it's not a great direction to go anyway, because "something seems very wrong".

-- Scott