Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named XXX: The following providers:
org.hibernate.ejb.HibernatePersistence
oracle.toplink.essentials.PersistenceProvider
oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider
Returned null to createEntityManagerFactory.
換成 Hibernate 就沒有這個問題。
經網上查找（ http://www.netbeans.com.cn/read.php?tid=775 ）和測試，這是由於項目帶有中文路徑的 BUG ！