Defined minimal java version

[sbernard31]

We should defined what could be the minimal java version requirement :

• for running,
• for building.

For running and for a library, I generally advice the minimal java version supported :

• https://adoptium.net/fr/support#roadmap
• https://www.oracle.com/java/technologies/java-se-support-roadmap.html

So that means java 8, this is bad news for library developer 😅 but this is better for library users.
AFAIK from a users point of view I don't know benefits to target a more recent version of java (but let me know if I'm wrong)
So depends if we really want it to be reused.

For building it's less important generally you can use more recent version and build binary for older jvm using --release
(see : eclipse-leshan/leshan#1412)

[bplessis-swi]

Is there a reason for digging up to java 11 or later ?
java 8 is on extended life support so it require paying oracle no ?

[sbernard31]

java 8 is on extended life support so it require paying oracle no ?

I understand this doesn't require paiement :
"***** The Extended Support uplift fee will be waived for the period October 2023 – January 2032 for Java SE 11. The Extended Support uplift fee will be waived for the period March 2022 - December 2030 for Java SE 8. During this period, you will receive Extended Support as described in the Oracle Technical Support Level sections of the Technical Support Policies."

And also I don't think there is cost for support with adoptium build.