CFV: New Project: ZGC

John Rose john.r.rose at
Thu Oct 26 23:23:48 UTC 2017

On Oct 26, 2017, at 8:42 AM, Volker Simonis <volker.simonis at> wrote:
> If no, why you propose ZGC at all and not contribute to
> Shenandoah? It's there since more than two years!  That you already
> worked on ZGC for some time as well doesn't count here because we (the
> OpenJDK community) couldn't see that and had no chance to contribute
> to it.

So, a proposed contribution "doesn't count" if it in any way overlaps
with previously contributed software?  Of course it counts.

As open-source people we are skeptical of closed-source projects,
but (a) they count intrinsically, as hard won experience (even if
won in the dark), and (b) when opened up, they count as welcome
help, previously inaccessible.

Your comments are very understandable (except for the bit I just
quoted), but try to see it from our viewpoint also.

"Why didn't you contribute to Shenandoah?"  Because we had an
internally funded alternative that seemed more promising to us,
which we couldn't share.  Is Oracle the only company with internally
funded changes to the OpenJDK?  No.  But we are one that is
aggressively out-streaming ours, now.

Oracle's new direction announced at JavaOne is that we are going
to be moving Java forward faster.  To move faster in this case is to
get ZGC out into the light of day, as quickly as possible.  I'm sorry
this seems unfair to you, when compared to actions in previous
years.  I don't think we were unfair, but even if we were, we are
on record as eager to distribute responsibility for OpenJDK
development fairly.  The current vote is our move to get our
very promising code out as quickly as possible.  I hope that's
enough reason to overlook any perception of unfairness.

Put another way:  Would you really prefer that we keep ZGC
wraps while we replay the Shenandoah cross-examination, to
some suggested number of months?  Wouldn't it be better to
get the code bases out there and then figure out what to do
with them?  Of course it would.

That's why I voted yes!

Do you have an alternative suggestion for accelerating a fair
and open examination of our sudden riches of GC technology?
That's what I want; I have to think that's what everyone wants.

Best wishes,
— John

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