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

[Strong Liu]

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