entitymanager

In the following code I am trouble with my injected EnitityManager, which always shows up as null ; public class GenericController extends AbstractController { @PersistenceContext(unitName = "GenericPU") private EntityManager em; protected ModelAndView handleRequestInternal( HttpServletRequest request, HttpServletResponse response) throws Exception { //(em == null) is always trigged if (em == null) throw new NullPointerException("em is null"); Collection<Generic> Generics = em.createNamedQuery("Generic.findAll").getResultList(); ModelAndView mav = new ModelAndView("Generic"); mav.addObject

I would like to have in Java SE @Stateless public class CarDAO { @Inject private EntityManager em; public Car findById(Long id) { return em.find(Car.class, id); } } @Singleton public class Application { @Inject private CarDAO carDAO; public void run() { Car car = carDAO.findById(44); System.out.println(car); } } public class EntryPoint { public static void main(String[] args) { Application application = // missing code application.run(); } } What I have to do to achieve that? I'm using postgres database, and maven in my project. I was already reading something about Weld (but it looks only

I'm using Java EE 7. I would like to know what is the proper way to inject a JPA EntityManager into an application scoped CDI bean. You can't just inject it using @PersistanceContext annotation, because EntityManager instances are not thread safe. Let's assume that we want our EntityManager to be created at the beginnig of every HTTP request processing and closed after the HTTP request is processed. Two options come into my mind: 1. Create a request scoped CDI bean which has a reference to an EntityManager and then inject the bean into an application scoped CDI bean. import javax.enterprise

if I have multiple threads, each use injector to get the EntityManager object, each use the em object to select a list of other class objects. Ready to be used in a for loop. If a thread finishes first and calls clear(), will that affect the other threads? Like the for loop will have exception? How about close()? If the answer is "It depends", what (class definition? method call?) and where (java code? annotation? xml?) should I look at to find out how is it depended? I did not write the source, I am just using someone else's library without documentation. Thank you. Here is full working

I have a java EE project using JPA (transaction-type="JTA"), hibernate as provider. I write my beans to handle the CRUD things. The program running in JBOSS 7 AS. I have an EntityManagerDAO : @Stateful public class EntityManagerDao implements Serializable { @PersistenceContext(unitName = "dtdJpa") private EntityManager entityManager; @TransactionAttribute(TransactionAttributeType.REQUIRED) public Object updateObject(Object object) { object = entityManager.merge(object); return object; } @TransactionAttribute(TransactionAttributeType.REQUIRED) public void createObject(Object object) {

i just set up a so far still quite minimal project maven/jpa/hibernate project, where i am trying to persist an object. My class is a quite simple one: @Entity public class Person { @Id @GeneratedValue private int id; private String name; } My persistence.xml is very basic as well: <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" version="2.0"> <persistence-unit name="Fahrplan_v2"> <class>model.Person</class>