[11u] Desupport building with Java 10?

[Lindenmaier, Goetz]

Hi Aleksey,

Theoretically you are right.
But do you think there will ever be a real use case of this?
The problem is that new OS distros are not supported by 
10 anyways.  See mac/windows aarch64 and the alpine port.

> the OS distro that is so special
I think we can move the burden to solve this issue to the
special distro and save the effort on our side.

Obviously, to solve this,
you build an old version of jdk11u with your build of jdk10. 
It's insecure anyways as jdk10 is not secure. With that
build of the old version you can again build the current jdk11u.

Best regards,
  Goetz.

> -----Original Message-----
> From: Aleksey Shipilev <shade at redhat.com>
> Sent: Thursday, February 17, 2022 9:25 AM
> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; jdk-updates-
> dev at openjdk.java.net
> Subject: Re: [11u] Desupport building with Java 10?
> 
> 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