100分问关于persistenceUnit的问题！高手请进！

在下用myeclipes5.5和weblogic10开发ejb3.0 project 在调用persistenceUnit时出现如下错误！请高手指教！
Cannot instantiate class: weblogic.jndi.WLInitialContextFactory

OpenJPA will now connect to the database to attempt to determine what type of database dictionary to use. To prevent this connection in the future, set your openjpa.jdbc.DBDictionary configuration property to the appropriate value for your database (see the documentation for available values).

调用代码如下：

public void showUserlist() {





		String sql = "select u from user u";

		factory=Persistence.createEntityManagerFactory("test");

 		EntityManager manager = factory.createEntityManager();

		Query q = manager.createQuery(sql);

		List list = q.getResultList();

		int len = list.size();

		for (int i = 0; i < len; i++) {

			User temp = (User) list.get(i);

			System.out.println(temp.getId());

			System.out.println("\n ");

			System.out.println(temp.getUserName());

		}

	}