Injection of EntityManager Example has been edited by David Blevins (Aug 08, 2008).

(View changes)



Shows use of @PersistenceContext to have an EntityManager with an EXTENDED persistence context injected into a @Stateful bean. An EJB 3 @Entity bean is used with the EntityManager to create, persist and merge data to a database.

If you need to use a TRANSACTION persistence context, see this example.

The source for this example is in the "injection-of-entitymanager" directory located in the available on the download page.

The Code

The Stateful bean

import javax.ejb.Stateful;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceContextType;
import javax.persistence.Query;
import java.util.List;

@Stateful(name = "Movies")
public class MoviesImpl implements Movies {

    @PersistenceContext(unitName = "movie-unit", type = PersistenceContextType.EXTENDED)
    private EntityManager entityManager;

    public void addMovie(Movie movie) throws Exception {

    public void deleteMovie(Movie movie) throws Exception {

    public List<Movie> getMovies() throws Exception {
        Query query = entityManager.createQuery("SELECT m from Movie as m");
        return query.getResultList();


The Entity bean

import javax.persistence.Entity;

public class Movie {

    private String director;
    private String title;
    private int year;

    public Movie() {

    public Movie(String director, String title, int year) {
        this.director = director;
        this.title = title;
        this.year = year;

    public String getDirector() {
        return director;

    public void setDirector(String director) {
        this.director = director;

    public String getTitle() {
        return title;

    public void setTitle(String title) {
        this.title = title;

    public int getYear() {
        return year;

    public void setYear(int year) {
        this.year = year;

The persistence unit

<persistence xmlns="" version="1.0">

  <persistence-unit name="movie-unit">

      <property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema(ForeignKeys=true)"/>

Writing a unit test for the example

public class MoviesTest extends TestCase {

    public void test() throws Exception {
        Properties p = new Properties();
        p.put(Context.INITIAL_CONTEXT_FACTORY, "org.apache.openejb.client.LocalInitialContextFactory");
        p.put("movieDatabase", "new://Resource?type=DataSource");
        p.put("movieDatabase.JdbcDriver", "org.hsqldb.jdbcDriver");
        p.put("movieDatabase.JdbcUrl", "jdbc:hsqldb:mem:moviedb");

        p.put("movieDatabaseUnmanaged", "new://Resource?type=DataSource");
        p.put("movieDatabaseUnmanaged.JdbcDriver", "org.hsqldb.jdbcDriver");
        p.put("movieDatabaseUnmanaged.JdbcUrl", "jdbc:hsqldb:mem:moviedb");
        p.put("movieDatabaseUnmanaged.JtaManaged", "false");

        Context context = new InitialContext(p);

        Movies movies = (Movies) context.lookup("MoviesLocal");

        movies.addMovie(new Movie("Quentin Tarantino", "Reservoir Dogs", 1992));
        movies.addMovie(new Movie("Joel Coen", "Fargo", 1996));
        movies.addMovie(new Movie("Joel Coen", "The Big Lebowski", 1998));

        List<Movie> list = movies.getMovies();
        assertEquals("List.size()", 3, list.size());

        for (Movie movie : list) {

        assertEquals("Movies.getMovies()", 0, movies.getMovies().size());

Curious on the InitialContext parameters used? See the Injection of DataSource Example for an explanation of how any Resource can be configured via properties in the TestCase itself or via an openejb.xml file.


Running the example is fairly simple. In the "injection-of-entitymanager" directory of the examples zip, just run:

$ mvn clean install

Which should create output like the following.

 T E S T S
Running org.superbiz.injection.jpa.MoviesTest
Apache OpenEJB 3.0    build: 20080408-04:13
INFO - openejb.home = /Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager
INFO - openejb.base = /Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager
INFO - Configuring Service(id=Default Security Service, type=SecurityService, provider-id=Default Security Service)
INFO - Configuring Service(id=Default Transaction Manager, type=TransactionManager, provider-id=Default Transaction Manager)
INFO - Configuring Service(id=movieDatabaseUnmanaged, type=Resource, provider-id=Default JDBC Database)
INFO - Configuring Service(id=movieDatabase, type=Resource, provider-id=Default JDBC Database)
INFO - Configuring Service(id=Default JDK 1.3 ProxyFactory, type=ProxyFactory, provider-id=Default JDK 1.3 ProxyFactory)
INFO - Found EjbModule in classpath: /Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager/target/classes
INFO - Configuring app: /Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager/target/classes
INFO - Configuring Service(id=Default Stateful Container, type=Container, provider-id=Default Stateful Container)
INFO - Auto-creating a container for bean Movies: Container(type=STATEFUL, id=Default Stateful Container)
INFO - Configuring PersistenceUnit(name=movie-unit)
INFO - Loaded Module: /Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager/target/classes
INFO - Assembling app: /Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager/target/classes
INFO - PersistenceUnit(name=movie-unit, provider=org.apache.openjpa.persistence.PersistenceProviderImpl)
ERROR - JAVA AGENT NOT INSTALLED. The JPA Persistence Provider requested installation of a ClassFileTransformer which requires
        a JavaAgent.  See
INFO - Jndi(name=MoviesLocal) --> Ejb(deployment-id=Movies)
INFO - Created Ejb(deployment-id=Movies, ejb-name=Movies, container=Default Stateful Container)
INFO - Deployed Application(path=/Users/dblevins/work/openejb-3.0/examples/injection-of-entitymanager/target/classes)
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 2.095 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

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