On 16/05/2019 15:18, Baesken, Matthias wrote:
Hello Alan,
I found
http://mail.openjdk.java.net/pipermail/core-libs-dev/2015-March/032106.html
and
http://mail.openjdk.java.net/pipermail/build-dev/2016-February/thread.html#16602
but without much details on real or potential performance improvements .
Both discussion threads are pretty old. I do not think they cover the
changes done in the meantime in jdk9 and higher in the java.util.zip
package .
I think a lot of coding there moved from C to Java , so the libz is used in JDK
less these days than in the "old times " .
Yes, the ZipFile implementation has changed significantly (many of the
motivations are listed in JDK-8142508) but the compression and checksum
(except CRC32C) will use libz. You'll see hotspot using it too, say when
running with -Xbootclasspath/a to add a JAR file to the boot class path.
There has many threads here and on core-libs-dev about using the bundled
vs. system zlib. It was an issue for the Linux distros in the early days
of OpenJDK as they have policies to not include copies of libraries that
the OS provides. At one point there was a patch proposing a XX option to
select the system vs. bundled zlib at run-time, the motivation being to
be able to switch to the Intel IPP implementation. It's impossible to
please everyone but I think the default that we settled on is probably
the best.
-Alan
