RFR [XXS]: 8242000: clean up list of environment variables printed in hs_err file

[David Holmes]

On 2/04/2020 8:11 pm, Baesken, Matthias wrote:
> Hi David ,
> 
> I think  "JAVA_COMPILER" is no longer needed,
>   (see a remark here that it was used to configure the JIT compiler  https://www.ibm.com/support/knowledgecenter/SSGU8G_12.1.0/com.ibm.sqlr.doc/ids_sqr_280.htm
>   but I cannot  find this any more in the current jdk/jdk codebase).

JAVA_COMPILER usage is ancient, back in 1.1 and 1.2 days IIRC :)

> Regarding JRE_HOME - I find  still some references in the source code, but not many .
> Could it be that some installers / tools outside the JDK still set/use it ?
> 
> jdk/src/hotspot/share/jfr/dcmd/jfrDcmds.cpp
> 345 _settings("settings", "Settings file(s), e.g. profile or default. See JRE_HOME/lib/jfr", "STRING SET", false),
> 
> jdk/src/hotspot/share/utilities/vmError.cpp
> 83 "JAVA_HOME", "JRE_HOME", "JAVA_TOOL_OPTIONS", "_JAVA_OPTIONS", "CLASSPATH",
> 
> /openjdk-jdk/src/java.base/share/man/java.1
> 1813 \f[CB]JRE_HOME/lib/jfr\f[R].

These uses are just commentary, I would suggest removing JRE_HOME and 
file a RFE for JFR to cleanup its references to JRE_HOME in jfrDcmds.cpp 
and the java command manpage.

But again these are just two more that I looked at in more depth. There 
may be others that need removing too.

Cheers,
David
-----

> So I would suggest to remove JAVA_COMPILER.  Maybe JRE_HOME too (but then also the other 2 references).
> 
> 
> Best regards, Matthias
> 
> 
> 
> -----Original Message-----
> From: David Holmes <david.holmes at oracle.com>
> Sent: Donnerstag, 2. April 2020 11:41
> To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> Subject: Re: RFR [XXS]: 8242000: clean up list of environment variables printed in hs_err file
> 
> Hi Matthias,
> 
> On 2/04/2020 4:55 pm, Baesken, Matthias wrote:
>> Hello, please review this very small cleanup change.
>>
>> When discussing the environment variables printed in the hs_err file, we
>> found that
>> some cleanup should be done , David  pointed out  :
>>
>>>> I think we can dispense with LD_ASSUME_KERNEL, and _JAVA_SR_SIGNUM is
>>>> used on Linux, BSD and AIX. :) Not for this change of course.
>>
>> Bug/webrev :
>>
>> https://bugs.openjdk.java.net/browse/JDK-8242000
>>
>> http://cr.openjdk.java.net/~mbaesken/webrevs/8242000.0/
> 
> That fixes the two examples I already found but the intent was to do a
> more thorough examination of all the variables to see if they are still
> relevant e.g is JRE_HOME still meaningful? What does JAVA_COMPILER do?
> The intent is to report env vars that can affect the execution of the JVM.
> 
> Cheers,
> David
> 
>> Thanks, Matthias
>>