[RFR] 8231171: remove remaining sun.java.launcher.pid references - was RE: sun.java.launcher.pid property usage

[Baesken, Matthias]

Hello, as discussed below ,   I want to cleanup  some older references to sun.java.launcher.pid.
Please review the following change.

After removal  of some code belonging  old  LinuxThreads   (JDK-8078513)   , the   sun.java.launcher.pid   handling code remained  but
 seems to be  obsolete these days .

Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8231171

http://cr.openjdk.java.net/~mbaesken/webrevs/8231171.0/

Best regards, Matthias


> 
> Hi David, thanks for the additional  information .
> I opened
> 
> https://bugs.openjdk.java.net/browse/JDK-8231171
> 
> 8231171: remove reamining sun.java.launcher.pid references
> 
>   to do the additional cleanup .
> 
> Best regards, Matthias
> 
> 
> > -----Original Message-----
> > From: David Holmes <david.holmes at oracle.com>
> > Sent: Mittwoch, 18. September 2019 03:16
> > To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-
> > dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> > Subject: Re: sun.java.launcher.pid property usage
> >
> > Hi Matthias,
> >
> > On 18/09/2019 12:18 am, Baesken, Matthias wrote:
> > > Hello,  while looking at some  atoi usages in the codebase I started to
> > wonder about the  "sun.java.launcher.pid"  property.
> > > Currently in java_md_solinux.c  the property is set on Linux only  by
> default
> > (code is guarded #ifdef __linux__ ).
> > > Later it is passed  to the int  variable _sun_java_launcher_pid
> > (arguments.cpp) and can be retrieved by sun_java_launcher_pid() .
> > > However only in src/hotspot/os/bsd/os_bsd.cpp it is really used.
> > >
> > > Is the property still supported (one would need to set it from user side on
> > the command line on non-Linux because it is not set by default on
> > bsd/macOS) ?
> > > Can the coding be removed (or should it enabled for BSD/Mac like we do
> > on Linux) ?
> > >
> > > The os_bsd comment mentiones the bug 6351349 :
> > >
> > > https://bugs.java.com/bugdatabase/view_bug.do?bug_id=6351349
> > > JDK-6351349 : On linux with the old thread lib, jps should return the same
> > PID as $!
> > >
> > > but this looks very old.
> >
> > That was the bug that added this code as it was needed on Linux with
> > LinuxThreads. The code was then removed on Linux under
> >
> > https://bugs.openjdk.java.net/browse/JDK-8078513
> >
> > The review thread starts here:
> >
> > http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2015-
> > May/014709.html
> >
> > I think we were focussed solely on cleaning up the hotspot Linux code
> > and didn't really look at the wider implication of the use of
> > sun.java.launcher.pid. The code in os_bsd.cpp was simply copied from the
> > Linux code without giving it any consideration - as you can tell from
> > the comment:
> >
> >    // With BsdThreads the JavaMain thread pid (primordial thread)
> >    // is different than the pid of the java launcher thread.
> >    // So, on Bsd, the launcher thread pid is passed to the VM
> >    // via the sun.java.launcher.pid property.
> >
> > where you can tell that Linux was simply replaced by Bsd, so we
> > reference the non-existent BsdThreads :(
> >
> > So yes this all seems to be dead code that should be removed - core-libs
> > folk will need to be involved of course as they own the launcher. :) It
> > looks like SetJavaLauncherPlatformProps() can be removed completely.
> >
> > Thanks,
> > David