RFR : 8195857 : Posix platforms : move os::is_headless_jre check coding to os::Posix and remove test for libmawt

[Baesken, Matthias]

Hi David, thanks for the comments.

> I'd need to do some checking but I think this may all be effectively
> dead code.

Please do the checking, maybe we can completely remove it.

Best Regards, Matthias


> -----Original Message-----
> From: David Holmes [mailto:david.holmes at oracle.com]
> Sent: Dienstag, 23. Januar 2018 11:30
> To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-
> dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> Subject: Re: RFR : 8195857 : Posix platforms : move os::is_headless_jre check
> coding to os::Posix and remove test for libmawt
> 
> Hi Matthias,
> 
> Some preliminary comments ...
> 
> On 23/01/2018 6:24 PM, Baesken, Matthias wrote:
> > Hello,  I  noticed that  os::is_headless_jre()  still checks  on the Posix
> platforms  for libmawt  which is not present any longer.
> 
> I wonder why that comment was put in but the code not changed ...
> 
> > Additionally the  os::is_headless_jre()   function could be  put in a central
> place at os_posix  to avoid code duplication.
> 
> I think you could simplify further and just define in os.cpp with three
> cases: windows, OS X, posix. I normally wouldn't suggest that but given
> Windows and OS X are always false, it's quite trivial.
> 
> That said this may simplify even further because I don't know if the
> concept of a headless JRE is even meaningful anymore. This what put in
> place in 2010 to support Java SE Embedded. We had a special build
> process that would remove the library from the JRE image, then a runtime
> check os::is_headless_jre() run during argument processing, that if
> true, caused the java.awt.headless property to be set to true (unless
> already set). I don't think we can even build a "headless JRE" any more.
> 
> I'd need to do some checking but I think this may all be effectively
> dead code.
> 
> Thanks,
> David
> -------
> 
> > Could you please review my change .
> >
> > Webrev :
> >
> > http://cr.openjdk.java.net/~mbaesken/webrevs/8195857/
> >
> > Bug :
> >
> > https://bugs.openjdk.java.net/browse/JDK-8195857
> >
> >
> >
> > Thanks, Matthias
> >