proposal to optimise the performance of the Jar utility
Alan.Bateman at oracle.com
Wed Apr 6 11:07:23 UTC 2011
mike.skells at talk21.com wrote:
> Not sure if this is too late for Java 7 but I have made some optimisations for a
> client to improve the performance of the jar utility in their environment, and
> would like to promite then into the main code base
It's been a long standing issue that creating JAR files with the jar
command has been very slow. Sherman did some good improvements in jdk7
, and I think they've been back-ported into Oracle jdk6 releases too.
Also Martin Buchholz and Jeremy Mason fixed another performance issue
for cases where the -C option is used to specify many directories .
Combined, this leads to some good improvements compared to older
releases of the JDK. Sherman has a blog entry  on this topic that
details some of the results.
I've no doubt more can be done and it sounds like you've made it your
mission to get it as fast as possible (which is great). I would suggest
sending a webrev or a patch so that the changes can be discussed. Also
it would be good to include some performance figures comparing the
implementation against jdk7. Just to set expectations, it probably is a
bit late in jdk7 for extensive or risky changes but we probably need to
see extend of the changes to judge that. If there are a lot of changes
then one idea is to push it into jdk8 first and let it bake there for a
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