Description of problem:
After stopping Guvnor web application and starting it again, the REST services stop working. Accessing any of the REST resources fails with the following error:

2011-12-15 17:22:28,299 ERROR [STDERR] (http-127.0.0.1-8080-2) java.lang.LinkageError: loader constraint violation: when resolving overridden method "com.sun.xml.bind.v2.runtime.MarshallerImpl.marshal(Ljava/lang/Object;Ljavax/xml/stream/XMLStreamWriter;)V" the class loader (instance of org/jboss/classloader/spi/base/BaseClassLoader) of the current class, com/sun/xml/bind/v2/runtime/MarshallerImpl, and its superclass loader (instance of <bootloader>), have different Class objects for the type javax/xml/stream/XMLStreamWriter used in the signature

Version-Release number of selected component (if applicable):
BRMS 5.3.0.DEV5

How reproducible:


Steps to Reproduce:

1. start server with Guvnor WAR deployed

2. import a repository and check the result of http://localhost:8080/jboss-brms/rest/packages

3. restart Guvnor
   - either in admin console
   - or using $JBOSS/bin/twiddle.sh like this:
> ./twiddle.sh -u <user> -p <password> -s localhost invoke jboss.web.deployment:war=/<war_name> <stop|start>

4. access http://localhost:8080/jboss-brms/rest/packages again and see server log for the exception
  
Actual results:
REST services stop working after restarting Guvnor (without stopping the server)

Expected results:
REST services should be available after restarting Guvnor (without stopping the server)

Additional info:
this is not issue for BRMS 5.2.0