EntityManager is null
问题 I am new to EJB, creating an application for fun/learning EJB following is the code. @Entity @Table(name = "PERSON", schema = "experiment") @NamedQuery(name = "Person.fetchAllPerson" , query = "select p from Person p") public class Person implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id") private Long id; @Column(name = "name", length = 500) private String name; @Column(name = "age") private