[news.eclipse.rt.eclipselink] Re: Equinox weaving configuration - Claslo

[shaun.smith@xxxxxxxxxx (Shaun Smith)]

Thomas Haskes wrote:
> ...
> Now when I start my application, I get a ClassNotFoundException on my
> entity classes, but only when I start the fragments
> org.eclipse.persistence.equinox and org.eclipse.equinox.weaving (which
> are required to start to get lazy loading working as mentioned in [1]).

You don't have to start those fragments; I don't think you can really.  In 
the example you deploy those fragments and start the javax.persistence 
bundle and then the org.eclipse.persistence.jpa bundle.  Finally you start 
your client bundle.

> If I dont start those fragments, everything works, but then theres no
> weaving at all(which is clear as the fragment are not started). It seems
> that I have to configure some more Bundle-Requirements or
> Buddy-Classloading directives, but I don't know where and what.

You don't have to use an Equinox specific buddy loading with EclipseLink.  
If it works without weaving then your config is probably ok.

One of the key issues for weaving is the requirement that framework 
fragments be co-located with the org.eclipse.osgi bundle.  In the example 
[1], all the bundles are in the same folder so the fragment loads 
properly.  The way Equinox is launched is key to this working and the 
config I describe is critical to success.  If you're running inside PDE 
then you need to checkout the source for Equinox (org.eclipse.osgi) from 
CVS.  See the comments on the Adaptor Hook [2] page for details.  By 
having the Equinox source in your dev environment when you deploy 
org.eclipse.osgi and the framework extension fragment 
org.eclipse.persistence.equinox.weaving are in the same folder.  Luckily, 
PDE launches Equinox in such a way that the fragments are loaded 
correctly--when I went outside PDE I soon discovered that launching 
Equinox with "java -jar org.eclipse.osgi_<version>" did not work, the 
framework extensions are loaded after the Adapter Hook framework has 
looked for extensions!  So, as I said, *luckily* PDE launches Equinox in a 
way that works.

> Any Ideas?

I've thrown out a bunch of background and hopefully this helps.  In my 
experience, the most common problem is the weaving extension either not 
being attached to org.eclipse.osgi or being attached after the Adaptor 
Hook framework has looked for extensions.  Making sure you launch Equinox 
as described should solve these issues. If this doesn't help can you post 
your short status (ss) which will show if the fragments are properly 
attached?

--Shaun

> Tom

> [1]
> http://wiki.eclipse.org/EclipseLink/Examples/OSGi/Equinox_Byte_Code_Weaving
[2] http://wiki.eclipse.org/Adaptor_Hooks