ClassNotFoundException encountered for file specified in persistence.xml in JBoss

Issue

• An application that uses JPA provided by TopLink results in the following error upon deployment:

  2010-09-20 12:19:22,212 ERROR
  [org.jboss.kernel.plugins.dependency.AbstractKernelController] (main)
  Error installing to Start: name=persistence.unit:unitName=#puUnit
  state=Create
  java.lang.ClassNotFoundException: 
              oracle.toplink.essentials.PersistenceProvider
  
  from
  BaseClassLoader@274874{VFSClassLoaderPolicy@105f759{name=vfsfile:/webadm_apps/jboss-eap-5.0/jboss-as/server/tdcs/deploy/TDCSQueryApp.jar/
  domain=ClassLoaderDomain@176086d
  

• The toplink libs such as toplink-essentials.jar, toplink-essentials-agent.jar are available in server/default/lib directory.

• Here is the persistance.xml is formatted as

  <?xml version="1.0" encoding="UTF-8"?>
  <persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
     <persistence-unit name="puUnit" transaction-type="RESOURCE_LOCAL">
     <provider>
        oracle.toplink.essentials.PersistenceProvider
     </provider>
     <non-jta-data-source>java:/ejb3ProjectDS</non-jta-data-source>
     <class>com.company.persistence.model.SomeDao</class>
     ...
  </persistence>