ERROR PropertyAccessException IllegalArgumentException occurred calling getter of...

[Angel J Gama]

Hi, I'm newby to Hibernate... I've read different tutorials and got up and running the examples but got problems when implementing on my own :S
I got an horrible:

Exception in thread "main" org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of com.enyel.hiphop.persistent.Alumno.matricula

Does any one have an idea what that means?
My db is about a "mini-forum":
- Tema: topic's class
- Mensaje: class for a topic's messages
- Alumno: class for author's data

Tema.java-----------------------------

public class Tema {
private Long id;
private Long autorID;
private Alumno autor;
private String titulo;
private String texto;
private List mensajes;

public Tema(){ }
 
public Long getId() { return this.id; }
public Long getAutorID() { return this.autorID; }
public Alumno getAutor() { return this.autor; }
public String getTitulo() { return this.titulo; }
public String getTexto() { return this.texto; }
public List getMensajes() { return this.mensajes; }
 
private void setId(Long id) { this.id = id; }
public void setAutorID(Long autorID) { this.autorID = autorID; }
public void setAutor(Alumno autor) { this.autor = autor; }
public void setTitulo(String titulo) { this.titulo = titulo; }
public void setTexto(String texto) { this.texto = texto; }
public void setMensajes(List mensajes) { this.mensajes = mensajes; }
}

Mensaje.java-------------------------

public class Mensaje {
private Long id;
private Long temaID;
private String texto;

public Mensaje(){ }
 
public Long getId() { return this.id; }
public Long getTemaID() { return this.temaID; }
public String getTexto() { return this.texto; }
 
private void setId(Long id) { this.id = id; }
public void setTemaID(Long temaID) { this.temaID = temaID; }
public void setTexto(String texto) { this.texto = texto; }
}

Alumno.java-----------------------------

public class Alumno {
//propiedades
private Long matricula;
private String nombre;

public Alumno() { }

public Long getMatricula() { return this.matricula; }
public String getNombre() { return this.nombre; }
 
public void setMatricula(Long matricula) { this.matricula = matricula; }
public void setNombre(String nombre) { this.nombre = nombre; }
}

Test.java-----------------------

public class Test {
  public static void main(String[] args) {
        Session session = SingletonSessionFactory.getSessionFactory().getCurrentSession();
        session.beginTransaction();
 
        Alumno a1 = new Alumno();
        a1.setMatricula(458793L);
        a1.setNombre("Pepe el Toro");
        session.save(a1);
 
        Tema tema = new Tema();
        tema.setAutor(a1);
        tema.setAutorID(a1.getMatricula());
        tema.setTitulo("Main topic example");
        tema.setTexto("this is the text for the main topic example");
        session.save(tema);
 
        session.getTransaction().commit();      
        SingletonSessionFactory.getSessionFactory().close();
  }
}

Alumno.hbm.xml-----------------------

  <class name="Alumno" table="Alumno">
    <id name="matricula" column="MATRICULA" type="long" unsaved-value="null">
  <generator class="assigned"/>
</id>
    <property name="nombre" column="NOMBRE" type="string" length="20"/>
  </class>

Tema.hbm.xml-------------------------

<class name="Tema" table="Tema">
    <id name="id" column="TEMA_ID" type="long" unsaved-value="null">
      <generator class="native"/>
</id>
 
<many-to-one name="autorID" column="MATRICULA" class="Alumno" not-null="true"/>
    <property name="titulo" column="TITULO" type="string" length="255"/>
    <property name="texto" column="TEXTO" type="text"/>
<bag name="mensajes" table="Mensaje" cascade="all" lazy="false">
<key column="TEMA_ID" not-null="true"/>
<one-to-many class="Mensaje" />
</bag>
  </class>

Mensaje.hbm.xml---------------------------

  <class name="Mensaje" table="Mensaje">
    <id name="id" column="MENSAJE_ID" type="long" unsaved-value="null">
      <generator class="native"/>
</id>
 
    <property name="texto" column="TEXTO" type="text"/>
  </class>

[Angel J Gama]

Also the error message says:

Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class

[Jaikiran Pai]

Just a really wild guess :

<property name="texto" column="TEXTO" type="text"/>

Try changing it to

<property name="texto" column="TEXTO" type="[B]String[/B]"/>

[Angel J Gama]

type="text" is just working fine... when I disable everything related to the relationship between "Tema" and "Alumno" everything just works fine, but when I 'enable-it' I'm getting the error.
It says is something about the getter method for the id and foreign key but I can't get exactly what is going wrong

[Mark Spritzler]

"Angel JGM",
Welcome to the JavaRanch.

We're a friendly group, but we do require members to have valid display names.

Display names must be two words: your first name, a space, then your last name. Fictitious names are not allowed.

Please edit your profile and correct your display name since accounts with invalid display names get deleted.

Thanks

Mark