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
