=== Make openjdk21 the default JAVA_VERSION

Links:
link:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272855[Issue 272855] URL: link:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=272855[]
link:https://docs.google.com/spreadsheets/d/17hmRQ0ShY4SHHVEkQBVxqK2G88fPZLriTzO26zXdjC4/edit?usp=sharing[Sheet tracking Work in Progress] URL: link:https://docs.google.com/spreadsheets/d/17hmRQ0ShY4SHHVEkQBVxqK2G88fPZLriTzO26zXdjC4/edit?usp=sharing[]

Contact: Ronald Klop <ronald@FreeBSD.org>

Having a vivid Java environment is useful for all kinds of applications of FreeBSD.

The default JAVA_VERSION in FreeBSD ports is changed from 8 to 21 on February 26th.
This was a major step in versions.
So quite some work was involved.
This is all done now.

All ports known to break were fixed and no regressions have been reported since.
The 2026Q2 ports branch will be the first stable ports branch having OpenJDK 21 as the default Java version.

* A big thank you to all people involved
* Work has been started to make 25 the new JAVA_DEFAULT in main during Q2
