[11u] RFR/RFA (S): 8253134: JMM_VERSION should remain at 0x20020000 (JDK 10) in JDK 11

[Volker Simonis]

On Tue, Sep 15, 2020 at 6:32 PM Hohensee, Paul <hohensee at amazon.com> wrote:
>
> Thanks for the review, Volker. You're right, I'll delete that sentence.
>
Thanks! I saw you've deleted the sentence in the CSR so I deleted it
in the bug as well. I've also added a "jdk11u-critical-request" label
now that CSR has been approved.

> Paul
>
> On 9/15/20, 8:40 AM, "Volker Simonis" <volker.simonis at gmail.com> wrote:
>
>     On Mon, Sep 14, 2020 at 11:25 PM Hohensee, Paul <hohensee at amazon.com> wrote:
>     >
>     > Please review this patch and CSR for 11.0.9. If approved, I propose tagging the issue with jdk11u-critical-request.
>     >
>     > Bug: https://bugs.openjdk.java.net/browse/JDK-8253134
>     > CSR: https://bugs.openjdk.java.net/browse/JDK-8253136
>     > Webrev: http://cr.openjdk.java.net/~phh/8253134/webrev.11u.00/
>     >
>     > JDK-8231209<https://bugs.openjdk.java.net/browse/JDK-8231209>, which was originally pushed to JDK 14, has been backported to 11.0.9 and 11,0.10-oracle. Those backports changed JMM_VERSION from 0x20020000 (JDK 10) to 0x20030000 (JDK 14), which introduced an incompatibility that was overlooked in the backport CSRs JDK-8247807<https://bugs.openjdk.java.net/browse/JDK-8247807> (11.0.9) and JDK-8248871<https://bugs.openjdk.java.net/browse/JDK-8248871> (11.0.10-oracle). JDK 11 users checking for JMM_VERSION == 0x20020000 will find 0x2003000 instead and possibly abort. The issue was first noticed as part of reviewing a backport of JDK-8185003<https://bugs.openjdk.java.net/browse/JDK-8185003> to JDK 8: see the Description in the corresponding CSR JDK-8251498<https://bugs.openjdk.java.net/browse/JDK-8251498>.
>     >
>     > For the reasons detailed there, JMM_VERSION in JDK 11 should be reverted to 0x20020000 (JDK 10), and the @since javadoc tag for com.sun.management.ThreadMXBean.getCurrentThreadAllocatedBytes should be changed from 14 to 11.0.9. If/when the JDK-8231209<https://bugs.openjdk.java.net/browse/JDK-8231209> backport to JDK 8 is approved for openjdk8u282, the @since tag should be changed to 8u282.
>     >
>
>     This all looks good to me. I've also reviewed and endorsed the CSR.
>
>     I'm only not sure about the last sentence: "If/when the JDK-8231209
>     backport to JDK 8 is approved for openjdk8u282, the @since tag should
>     be changed to 8u282". Not sure if we should really do that? If
>     somebody reads that in jdk11u he could think that the change must be
>     in 11.0.0 and later as well, but that's not true.
>
>     If somebody reads it in the 8u282 API he might think the same (and
>     that it is in 9 & 10 but those two are hopefully not used by anybody
>     any more), and there's no way to fix that. But I'd personally leave it
>     as 11.0.9 in jdk11u.
>
>     Best regards,
>     Volker
>
>     > Thanks,
>     > Paul
>     >
>