LZMA compression for jpkg

[Tom Marble]

On 06/07/2011 01:06 PM, Chris Hegarty wrote:
> I have been looking into the possibility of using LZMA compression ( following on from Dalibors work last year ) for the jmod packages. Initial results look positive.
It's true that we have an opportunity to do something new here!

Note that the Java Module-System Requirements — DRAFT 12 [0]
does list this as a goal (with pack200 for jars of course).

While where considering compression techniques we might as
well jump to xz (an improvement over lzma) [1].

> I've been using a Java implementation from the latest LZMA 9.20 SDK [1]. I modified jpkg to use LZMA compression [...]
> The debian packages that get built during the modules build are still smaller than these lzma-ized jmod files. 

With our current Jigsaw project in Debian we are looking at how
to create policy compliant packages [2]. I highly suspect we
will need to rethink the current approach of having jpkg doing
the work and, instead, collaborating with native debhelper tools [3].
Point being that we should probably avoid the current *.deb
packaging as much of a baseline.

In this context it is important to note that classically
Debian source packages used to accept only upstream tarballs
in gzip but are evolving to include bzip2 and xz in
later releases. [4]

Regards,

--Tom

[0] http://openjdk.java.net/projects/jigsaw/doc/draft-java-module-system-requirements-12#java-native-module-file-format
[1] http://tukaani.org/xz/
[2] http://wiki.debian.org/SummerOfCode2011/Jigsaw
[3] http://joey.kitenet.net/code/debhelper/
[4] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=556407