RFR: 8368960: Adjust java UL logging in the build [v3]

[David Holmes]

On Sat, 4 Oct 2025 11:46:02 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> make/autoconf/boot-jdk.m4 line 447:
>> 
>>> 445:   UTIL_ADD_JVM_ARG_IF_OK([-Duser.language=en -Duser.country=US],boot_jdk_jvmargs,[$JAVA])
>>> 446: 
>>> 447:   UTIL_ADD_JVM_ARG_IF_OK([-Xlog:all=warning:stderr],boot_jdk_jvmargs,[$JAVA])
>> 
>> This is not sufficient you have to disable the warnings on stdout, not just enable them on stderr.
>
> So should I set something like `-Xlog:disable` _additionally_ to the  `-Xlog:all=warning:stderr ` ?
> The whole UL sometimes is strange and a bit confusing to me.

As @MBaesken wrote in JBS: `-Xlog:all=off ` should disable logging on stdout. However, I just experimented with this and seems that enabling warnings on stderr is disabling them on stdout - at least I only see the warning reported once (even though the log configuration says they are enabled on both ??) .

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PR Review Comment: https://git.openjdk.org/jdk/pull/27588#discussion_r2409168309