apache-maven: bump java version? & looking for SWT for NetBSD

[Thomas Klausner <wiz%netbsd.org@localhost>]

Hi!

I was trying to compile https://github.com/a-sit/PDF-Over, a Java
program, for NetBSD. It uses maven to build, but maven didn't allow
building it because it doesn't support Java 21.

That is fix by changing
USE_JAVA2=      7
to
USE_JAVA2=      21
in its Makefile, which changes the used JDK from 7 to 21.

Does anyone have a problem with changing that?

I couldn't get the program to compile, since it wants to use SWT and
there is no SWT for NetBSD (at least not on Maven Central). Does
anyone have a SWT for NetBSD?

 Thomas