Building/distributing more than one VM in a single JDK distribution

[Vladimir Petko]

Hi,

> I vaguely remember Debian folks building the VM that carried both Server and Zero in the same
bundle.

I think the only instance of configuring two vms is i386[1], and since
x86 hotspot is being retired, the package only builds zero vm[2].
Server and Zero are built in separate steps[3].

Best Regards,
 Vladimir.
[1] https://salsa.debian.org/openjdk-team/openjdk/-/blob/master/debian/rules?ref_type=heads#L426
[2] https://salsa.debian.org/openjdk-team/openjdk/-/blob/master/debian/rules?ref_type=heads#L63
[3] https://salsa.debian.org/openjdk-team/openjdk/-/blob/master/debian/rules?ref_type=heads#L423

On Wed, Mar 12, 2025 at 6:12 AM Aleksey Shipilev <shipilev at amazon.de> wrote:
>
> Hi Magnus,
>
> On 11.03.25 11:53, Magnus Ihse Bursie wrote:
> > Hence, I see no need anymore to keep the ability to build more than one
> > variant of Hotspot at the same time. I propose we drop this
> > functionality, which will allow for us to clean up and remove a lot of
> > complexity in several areas of the codebase. (Just to be clear: I do not
> > propose removing zero or minimal, I'm just saying that you need to build
> > *only* the zero or minimal JVM if that is what you want.)
> >
> > Feedback, thoughts?
>
> For the multi-variant bundle:
>
> I vaguely remember Debian folks building the VM that carried both Server and Zero in the same
> bundle. Matthias Klose showed me some of the scripts and related build errors. I cannot recall the
> reason for this.
>
> For the multi-JVM bundle:
>
> Multi-JVM bundles have a place in the world. You can currently frankenstein such a bundle from
> several JDK builds from the exact same source. The build support for them would be nice, and I would
> have thought the current multi-variant build support would serve as stepping stone towards it. I
> have not explored this in current build system at all, though -- so maybe you already know the
> answer to this from maintainability perspective. "Too hard, keep frankensteining them" is the
> acceptable answer :)
>
> I know two use cases for multi-JVM bundles:
>
> 1. Shipping fastdebug JVM along with release JVM in the same bundle. This allows users to quickly
> select assertions-rich or non-optimized JVM for debugging sessions, with a flip of the command line
> switch, like -fastdebug / -slowdebug. See for example: https://builds.shipilev.net/openjdk-jdk/
>
> 2. Shipping completely different JVM in the same bundle. I believe this is how Espresso/Truffle does
> it with -server / -truffle. See: https://www.graalvm.org/latest/reference-manual/espresso/
>
> Thanks,
> -Aleksey