Hibernate 5 :- org.hibernate.MappingException: Unknown entity

the method that i buid a sessionFactory is followed ,which will cause the MappintException of Unknown entity Configuration configuration = new Configuration(); configuration.configure(); ServiceRegistry sr = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build(); SessionFactory sf = configuration.buildSessionFactory(sr); Solution——- remove the codes of serviceRegistry configuration.configure(); //serviceRegistry = new StandardServiceRegistryBuilder() // .applySettings(configuration.getProperties()).build(); sessionFactory = configuration.buildSessionFactory(); Analyse the first code works fine for Hibernate 4.3.5, but the same code has the same issue for Hibernate 5. When you do configuration.buildSessionFactory(sr), using Hibernate 5, Configuration losts all information about mapping that gets by call configuration.configure(). So you should use SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();

instead.