jdk6 missed method sun.misc.Unsafe#copyMemory(Object, long, Object, long, long)

[Andrew Hughes]

----- Original Message -----
> I am extremely reluctant to approve any changes to openjdk6 at this
> date.

Why?  As I've previously mentioned, we have a whole pile of patches
(mostly backports, but some additions too) that ideally need to go upstream.
OpenJDK 6 as it stands is quite outdated with respect to the proprietary
version.

> But I am willing to listen to the community if there is a very good
> justification to get this in.
> 
> -kto
> 
> On Jan 15, 2013, at 2:21 AM, Alex Kasko wrote:
> 
> > Hello,
> > 
> > Method sun.misc.Unsafe#copyMemory(Object,long,Object,long,long) is
> > used in popular Snappy codec implementation [1, 2].
> > 
> > It's present in openjdk-7 and in late updates of Oracle jdk6. But
> > it's missed in openjdk-6. Its native implementation is available
> > in jdk6 hostspot [3], though. As far as I understood, it was
> > removed from jdk6 codebase during preparation to first jdk6
> > release [4]. I tried to restore it in jdk6 sources (left hotspot
> > untouched) and it seems to work well.
> > 
> > Can someone clarify, whether it's safe to patch sun.misc.Unsafe and
> > use this method in jdk6?
> > 
> > 
> > [1] https://github.com/dain/snappy#snappy-in-java
> > [2]
> > https://github.com/dain/snappy/blob/01f0a37ca40196e08336532ea6d328eb3ed22b67/src/main/java/org/iq80/snappy/UnsafeMemory.java#L101
> > [3]
> > http://hg.openjdk.java.net/jdk6/jdk6/hotspot/file/cd74fab0a5e3/src/share/vm/prims/unsafe.cpp
> > [4]
> > http://hg.openjdk.java.net/jdk6/jdk6/jdk/diff/39e8fe7a0af1/src/share/classes/sun/misc/Unsafe.java
> > 
> > --
> > Regards,
> > Alex Kasko
> 
> 

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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