Using JPA2 in Tomcat 6: @PersitenceContext doesn't work, EntityManager is null
jpa-2.0, jsf-2
Solution
Tomcat is not a Java EE container, so there are limitations related to container managed factories and dependency injection. Among others, you need to manually create the `EntityManagerFactory` and the `EntityManager`.
Hibernate documentation isn't clear on that, so here's the Eclipselink one: Tomcat/JPA tutorial. Check the "Limitations to JPA" section, this applies as good to Hibernate.
See also:
- Best practice to get EntityManagerFactory
Problem
I am using JSF2 with Pure JPA2. But the problem is with entityManager, ``` @PersistenceContext private EntityManager entityManager; ``` Here entityManager is not getting injected and always null. Can some one please help me what is wrong in my code. Here is my configuration. User.java ``` @Entity @Table(name="USER") public class User { private int id; private String name; private String surname; @Id @SequenceGenerator(name="user_id_seq_gen", sequenceName="USER_ID_GEN_SEQ", allocationSize=1) @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="user_id_seq_gen") @Column(name="ID", unique = true, nullable = false) public int getId() { return id; } public void setId(int id) { this.id = id; } @Column(name="NAME", unique = true, nullable = false) public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name="SURNAME", unique = true, nullable = false) public String getSurname() { return surname; } public void setSurname(String surname) { this.surname = surname; } } ``` persistence.xml ``` <?xml version="1.0" encoding="UTF-8"?> <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="testUnit" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <non-jta-data-source>java:/comp/env/testDS</non-jta-data-source> <class>com.user.external.test.User</class> <exclude-unlisted-classes>false</exclude-unlisted-classes> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/> <property name="hibernate.max_fetch_depth" value="6"/> <property name="hibernate.show_sql" value="false"/> <property name="hibernate.format_sql" value="true"/> </properties> </persistence-unit> </persistence> ``` Tomcat Server.xml ``` <Context docBase="usertools" path="/usertools" reloadable="true"> <ResourceLink name="testDS" global="testDS" type="javax.sql.DataSource"/> </Context> ``` TestBean.java ``` @ManagedBean(name="testBean") @ViewScoped public class TestBean implements Serializable{ @ManagedProperty("#{testService}") private ITestService testService; public void saveData(User user){ testService.saveUser(user); } public void setTestService(ITestService testService){ this.testService = testService; } public ITestService getTestService(){ return testService; } } ``` TestServiceImpl.java ``` @ManagedBean(name="testService") @ApplicationScoped public class TestServiceImpl implements ITestService { @ManagedProperty(value="#{testDAO}") private ITestDAO testDAO; public void saveUser(User user){ testDAO.saveUser(user); } public void setTestDAO(ITestDAO testDAO){ this.testDAO = testDAO; } public ITestDAO getTestDAO(){ return testDAO; } } ``` TestDao.java ``` @ManagedBean(name = "testDAO") @ApplicationScoped public class TestDAO implements ITestDAO { @PersistenceContext private EntityManager entityManager; // is null public void saveUser(User user){ entityManager.persist(user); // Getting Null Pointer Here.... } public void setEntityManager(EntityManager entityManager) { this.entityManager = entityManager; } public EntityManager getEntityManager() { return entityManager; } } ``` I have tried with @PersistenceContext name & unitName attributes. But still it is not working. Also tried with resource config in web.xml ``` <persistence-context-ref> <persistence-context-ref-name>testUnit</persistence-context-ref-name> <persistence-unit-name>testUnit</persistence-unit-name> </persistence-context-ref> <resource-ref> <description>DB Connection</description> <res-ref-name>testUnit</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> ``` Still No Luck. Can some one please help me.