jpa-2.0

EntityManager is not thread-safe by definition. Servlets specs says that in non-distributed environment and without implementing SingleThreadModel , there is only one servlet instance per definition . Therefore, in Java EE when you inject an EntityManager through the @PersistenceContext into Servlet's field - it's not thread safe: public class MyServlet extends HttpServlet { // Not thread-safe, should be using EMF instead. @PersistenceContext private EntityManager em; } Is this correct to say that even though the default scope of Spring beans is singleton, the EntityManager is thread-safe as

When i was in college learning about web programming, they told us about hibernate. We used it for a while, i even had the chance to work with it in a real scenario in a company for almost 8 months. Now that i completely switching to Java EE 6 ( Im in love :) ), I use JPA for my ORM needs. It is being a few months since i use it, but i dont really understand what are the differences between one and other. Why some people say one or other is better or worse? The way i do my mappings and annotations in both is almost the same... Maybe you can solve some of my doubts: -What are the advantages and

@Entity @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @Table(name = "company_policies") @DiscriminatorColumn(name = "rule_name") public abstract class AbstractPolicyRule implements Serializable { @Transient private static final long serialVersionUID = 1L; @Id @GeneratedValue private Long id; private String value; ... } _ @Entity public class Category implements Serializable { @Transient private static final long serialVersionUID = 1L; @Id @GeneratedValue private Long id; @Column(name = "category_name") private String name; @OneToMany(fetch = FetchType.EAGER, cascade = { CascadeType.ALL

I'm using JPA 2.0 and EclipseLink 2.2.0. I have a @MappedSuperclass, AbstractEntity, that is the basis for all my entities providing PK and auditing columns. I want to have another @MappedSuperclass extend that class and be the root for a TABLE_PER_CLASS inheritance strategy. At present, when building with Maven I receive header errors. Are multiple @MappedSuperclass allowed in an inheritance hierarchy? Mikko Maunu Multiple mapped superclasses are allowed in same inheritance hierarchy. It is not directly said so in specifications, but JPA 2.0 specification does not explicitly prohibit multiple

I have the following Entities; Ticket contains a set of 0,N WorkOrder: @Entity public class Ticket { ... @OneToMany(mappedBy="ticket", cascade = CascadeType.ALL, fetch = FetchType.LAZY) private List<WorkOrder> workOrders = null; ... } @Entity public class WorkOrder { ... @ManyToOne @JoinColumn(nullable = false) private Ticket ticket; } I am loading Tickets and fetching the attributes. All of the 0,1 attributes present no problem. For workOrders, I used this answer to get the following code. CriteriaBuilder criteriaBuilder = this.entityManager.getCriteriaBuilder(); CriteriaQuery<Ticket>

The Hibernate EntityManager documentation states , that: You may use a combination of all three together, annotations without JPA programming interfaces and lifecycle, or even pure native Hibernate Core, depending on the business and technical needs of your project. You can at all times fall back to Hibernate native APIs, or if required, even to native JDBC and SQL. Code that uses the JPA API (EntityManager) is clearly more portable (even with occasional fallbacks to Hibernate Core). But would I have any advantages when using purely Hibernate Core? I wonder, if the JPA 2 model really fits on

I have a JPA 2 application ( with Hibernate 3.6 as the JPA implementation ) that uses Postgresql ( with the 9.0-801.jdbc3 JDBC driver ). I am having trouble mapping "timestamp with time zone" fields into my JPA entities. Here is an example: CREATE TABLE theme ( id serial NOT NULL, # Fields that are not material to the question have been edited out run_from timestamp with time zone NOT NULL, run_to timestamp with time zone NOT NULL, CONSTRAINT theme_pkey PRIMARY KEY (id ), CONSTRAINT theme_name_key UNIQUE (name ) ) I have tried to map as follows: @Entity @Table(schema = "content", name = "theme