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From Simone Tripodi <>
Subject Re: [sandbox] class scanning + karma requests
Date Fri, 22 Jul 2011 14:20:37 GMT
Hi all guys!
That sounds really interesting!!!
I think that bringing the new ideas in existing [meiyo] APIs would
allow us releasing a new component soon!
Thanks in advance for your help and interesting, looking forward to
hear from you soon!!!

On Fri, Jul 22, 2011 at 11:41 AM, Mark Struberg <> wrote:
> Hi!
> Jakob Korherr (apacheId jakobk) is also interested and did some work in this area in
MyFaces and OWB already.
> There are 2 main parts in this project
> a.) A classpath scanner which does _not_ use Class.getDeclaredXxx etc, since this allocates
memory in the ClassLoader which cannot get freed up later. In a mid sized project this leads
to getting 100MB of PermGenSpace easily! This is what Davids xbean-finder fixes already by
just scanning the structure from the bytecode directly.
> b.) Lots of EE apps need to scan the classpath for annotations (e.g. MyFaces, OpenWebBeans,
Tomcat, OpenEJB, etc). So this part is done redundantly a few times when starting the server.
I hacked a quick API + SPI to do all this in one go. The trick is to introduce a register
mechanism where classscan-clients can register their needs before the scan gets performed.
> We like to do this at commons because it's really decoupled from all the single projects
and could be useful for a lot more projects which added some kind of annotation processing
> LieGrue,
> strub
> --- On Fri, 7/22/11, Matt Benson <> wrote:
>> From: Matt Benson <>
>> Subject: [sandbox] class scanning + karma requests
>> To:
>> Cc:, "Gerhard Petracek" <>
>> Date: Friday, July 22, 2011, 4:30 AM
>> First, Simo added [meiyo] to the
>> sandbox.  Now, some of the guys from
>> the various JEE-related communities have expressed interest
>> in working
>> with class scanning here at Commons.  What we would
>> propose to do is
>> start with the code of Geronimo's xbean-finder, which scans
>> classes by
>> reading bytecode to populate meta-structures, thereby
>> sparing permgen
>> space whenever possible.  We plan to carefully prune
>> and polish that
>> code, pull in the best ideas from [meiyo] (Simo and/or any
>> of the rest
>> of you Commons developers are of course welcome to
>> participate as
>> always!), and add a single-scan SPI strategy to allow the
>> majority of
>> consumers to share the impact of scanning.  For my own
>> part, I hope to
>> be able to contribute such that the final API can
>> accommodate most if
>> not all conceivable use-cases for classpath scanning, while
>> not
>> becoming too unwieldy.  We'd like to get started ASAP
>> (and obviously
>> nothing stops me from going ahead and taking the first
>> steps).  I
>> would also request our new chair grant sandbox karma to:
>> struberg (Mark Struberg)
>> dblevins (David Blevins)
>> gpetracek (Gerhard Petracek}
>> Thanks,
>> Matt
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