[11u] Desupport building with Java 10?

[Aleksey Shipilev]

On 2/17/22 11:04, Lindenmaier, Goetz wrote:
> Hi,
> 
> OpenJDK has the policy that each jdk should be able to
> be bootstrapped with the previous Java version.
> See also DEFAULT_ACCEPTABLE_BOOT_VERSIONS [1].
> This makes sense for new Java versions but not for
> updates of LTSes.  For jdk11u, using a Java 10 jdk
> for bootstrapping even is a security issue as there
> is no maintained jdk10.
> 
> On the other side we had to fix a few changes in
> the past to work with Java 10.  We should avoid this
> effort.
> 
> I propose to give up supporting Java 10 in the build
> in 11.0.16 and to change DEFAULT_ACCEPTABLE_BOOT_VERSIONS
> accordingly.
> 
> If there are no objections I'll do the corresponding
> change for 11.0.16.

As much as I would enjoy seeing this, there is a little logistic problem here: the initial 
bootstrapping the 11u build without having any 11u build. The "telescoping builds" -- 8 bootstraps 
9, 9 bootstraps 10, 10 bootstraps 11 -- provides the logistical continuity here.

Having the downloadable 11u build from some vendor only partially solves it. Consider the OS distro 
that is so special it is not covered by any existing vendor 11u build, that is, any 11u build not 
from this OS distro straight away fails to run. Now you want to produce the OS-specific 11u build 
there. But 11u build requires a 11u build. What do you do?

-- 
Thanks,
-Aleksey