[hibernate-dev] classloading issue when trying to add envers to as7

[Steve Ebersole]

I remember Scott and I discussing this exact issue.  Unfortunately I do 
not remember the specifics.  java.util.ServiceLoader#load(Class<S> 
service) does use the TCCL, but I think that the end result of our 
discussion was this is ok.

We need to have this call be able to locate services both within the 
module classloader as well as within the classloader that ikncludes the 
user app.  Scott, is there a single classloader that covers both of 
those cases that we could use?

On 06/16/2011 06:54 AM, Strong Liu wrote:
> Hi there,
>
> first of all, I have finished this task, and test pass.
> but :), i have to make the following changes, i'd like to hear you guys' thoughts before i go to much away.
>
> 1. adding envers into org.hibernate module in as7, so user's app can see both hibernate and envers class
> (with an separate envers module i ran into some cycle dependency issue)
>
> 2. envers throws "listeners were not registed" exception, means hibernate's IntegratorServiceImpl can't see envers class/resource
>
> IntegratorServiceImpl is using java.util.ServiceLoader#load(Class<S>  service), which internally using TCCL, (I think)
> that's the reason  why core can't see envers' integrator.
>
> so, i created a custom ServiceLoader which use ClassLoaderService to find the integrator, but this doesn't work either.
> since, we need org.hibernate.service.classloading.internal.ClassLoaderServiceImpl#locateResources first (META-INF/services/org.hibernate.integrator.spi.Integrator) and ClassLoaderServiceImpl using resourceClassLoader to do this.
> by default, resourceClassLoader is set to applicationClassLoader in ClassLoaderServiceImpl.
>
> then, i changed IntegratorServiceImpl to use java.util.ServiceLoader#load(Class<S>  service, IntegratorServiceImpl.class.getClassLoader()
> ), test pass, but this of course is not the fix.
>
> so, i changed the custom ServiceLoader to use classLoaderService to locateResources first, and using ServiceLoader.class.getClassLoader() to reload the resource again.
>
> here are the changes:
> https://github.com/stliu/hibernate-core/commit/09ce5defabea8cfb87d06c3d7b9bc1a2c613f62c
> https://github.com/stliu/jboss-as/commit/616237755626672157fb2ae565fadb16cf47af89
>
> thoughts?
>
> -----------
> Strong Liu<stliu at hibernate.org>
> http://hibernate.org
> http://github.com/stliu
>

-- 
Steve Ebersole <steve at hibernate.org>
http://hibernate.org