That seems like it would work, since the CFCL and HiveMindClassPool
work together to add and search ClassLoaders as needed.
On 7/21/06, Knut Wannheden <[EMAIL PROTECTED]> wrote:
Hi all,
I've noticed that users on multiple occasions now have reported
problems with the class loading in HiveMind. Usually I think the
problem is that the thread context class loader isn't set up properly.
And that's what HiveMind uses both to find hivemodule.xml descriptors
(when the registry is constructed in the default manner) and also as
the class loader for Javassist when creating and instrumenting classes
(using the HiveMindClassPool).
The class loader used for the module descriptor loading is fairly easy
to change to something different, but the class loader used by
Javassist is hard wired to the thread context class loader. Of course
the user can manually set the thread context class loader to something
different.
One problem with the Javassist class loading in HiveMind that's come
up a few times now is during the registry startup phase when the
Startup service is instrumented with the writeReplace() method. An
exception like the following will be thrown:
org.apache.hivemind.ApplicationRuntimeException: Unable to add method
java.lang.Object writeReplace() to class $Runnable_10b95a29c5e:
[source error] no such class:
org.apache.hivemind.internal.ser.ServiceSerializationHelper
Javassist can't find the ServiceSerializationHelper class.
I was wondering if we could solve this w/o having the user to set the
thread context class loader. Right now Javassist will use a
ClassFactoryClassLoader class loader which has the system class loader
as it's parent and the thread context class loader as a class loader
it will delegate to (a child class loader). Would it make sense to
setup the ClassFactoryClassLoader with the class loader which loaded
the HiveMind classes as its parent? I.e. add the following default
constructor:
public ClassFactoryClassLoader()
{
super(ClassFactoryClassLoader.class.getClassLoader());
}
Then at least Javassist shouldn't have problems with loading
ServiceSerializationHelper.
--knut
--
Howard M. Lewis Ship
Independent J2EE / Open-Source Java Consultant
Creator and PMC Chair, Apache Tapestry
Creator, Jakarta HiveMind
Professional Tapestry training, mentoring, support
and project work. http://howardlewisship.com
