Problem with JPA inheritance

nbhatia · **Joined:** Sun Sep 25, 2005 11:35 pm **Posts:** 57

I have a very simple object hierarchy in my app which uses JPA for inheritence:

Code:

@Entity
@Inheritance(strategy=InheritanceType.JOINED)
public abstract class Party {
    private Long id;

    @Id @GeneratedValue
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
}

Code:

@Entity
public class Person extends Party {
    private String firstName;
    private String lastName;
    
    public Person() {
    }
    
    public Person(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    @NotNull
    @Length(min = 3, max = 40)
    @Pattern(regex="[a-zA-Z]+", message="First name must only contain letters")
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    @NotNull
    @Length(min = 3, max = 40)
    @Pattern(regex="[a-zA-Z]+", message="Last name must only contain letters")
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

I am able to save and retrieve the Person object in my tests. However, when JBoss tries to load the persitence unit, it gives me the following exception:

Code:

07:48:46.828 WARN  [org.jboss.system.ServiceController] Problem starting service persistence.units:ear=myapp-1.0-SNAPSHOT.ear,unitName=myappDatabase
org.hibernate.AnnotationException: No identifier specified for entity: myapp.domain.party.Party
   at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:627)
   at org.hibernate.cfg.AnnotationConfiguration.processArtifactsOfType(AnnotationConfiguration.java:452)
   at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:268)
   at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1115)
   at org.hibernate.ejb.Ejb3Configuration.buildMappings(Ejb3Configuration.java:1233)
   at org.hibernate.ejb.EventListenerConfigurator.configure(EventListenerConfigurator.java:154)
   at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:869)
   at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:407)
   at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:126)
   at org.jboss.ejb3.entity.PersistenceUnitDeployment.start(PersistenceUnitDeployment.java:246)

Clearly, I have specified an identifier for the Party object. Why is JBoss complaining?

Thanks.
Naresh

carlolf · **Posted:** Wed Oct 15, 2008 6:02 am

do you have a file named 'persistence.xml' in the directory META-INF defined? and did you define your entity classes in this file?

here is an example of persistence.xml:

Code:

<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_1_0.xsd"
             version="1.0">

   <persistence-unit name="prj">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>java:/prjDS</jta-data-source>

      <mapping-file>META-INF/orm_prj.xml</mapping-file>

      <class>org.prj.base.domain.Check</class>
  (....)