Eclipselink ClassCastException

Question

Hi,
I already have checked for similar errors on this forums but no one seems to work. We are really stuck on this.
We are developing JPA 1.0 / eclipselink 2.0 / struts web application project on WebLogic Integration 10g Release 3 (10.3.1.0) which I am pretty sure it is using WebLogic server 10.3.1.0, note that we don't need JPA 2.0 functionality. Unfortunatelly we are facing constant java.lang.ClassCastException errors when trying to access to an jpa entity. The strange thing is that on the first attempt all is working fine, but after modifing code or redeploying we get those ClassCastException errors (after restarting the server all is working fine again).
We are using Application-Managed Entity Managers (we get our persistence context by using the createEntityManager method of javax.persistence.EntityManagerFactory). We are not using Container-Managed Entity Managers (@PersistenceContext
EntityManager em), although we are interested in this solution too.
** The code **
EntityManagerFactory emf = Persistence.createEntityManagerFactory("fwk");
EntityManager em = emf.createEntityManager();
TUsuario usuario = new TUsuario();     
try {
//query
usuario = (TUsuario) query.getSingleResult();
catch{...}
** persistence.xml **
<persistence-unit name="fwk" transaction-type="JTA">
          <provider>
               org.eclipse.persistence.jpa.PersistenceProvider
          </provider>
          <jta-data-source>fwk-des.DataSource</jta-data-source>
          <class>com.caprabo.panelFwk.integration.jpa.TUsuario</class>
          <properties>
               <!-- managed transaction and enlisted configuration -->
               <property name="javax.persistence.transactionType" value="JTA" />
               <property name="connection.datasource" value="fwk-des.DataSource" />
               <property name="eclipselink.jdbc.driver" value="oracle.jdbc.driver.OracleDriver" />
               <property name="eclipselink.target-server" value="WebLogic_10" />
               <property name="eclipselink.target-database" value="Oracle" />
               <property name="eclipselink.logging.level" value="FINE"/>
               <property name="eclipselink.persistence-context.reference-mode" value="WEAK"/>
          </properties>
     </persistence-unit>
** entity **
package com.caprabo.panelFwk.integration.jpa;
@Entity()
@Table(name="T_USUARIO")
public class TUsuario implements Serializable {
     //default serial version id, required for serializable classes.
     private static final long serialVersionUID = 1L;
     @Id()
     @Column(name="USUARIO_ID_PK", unique=true, nullable=false, length=8)
     private String usuarioIdPk;
We have already tried this without any success:
- eclipselink.jar javax.persistence_1.0.0.jar into manifest.mf
- eclipselink.jar javax.persistence_1.0.0.ja into ear, or into project WebContent\WEB-INF\lib
- modify weblogic-application.xml:
<wls:prefer-application-packages>
          <wls:package-name>javax.persistence.*</wls:package-name>
          <wls:package-name>org.eclipse.persistence.*</wls:package-name>
</wls:prefer-application-packages>
Thanks
Javier

Answer 1

user13394432 wrote:
I am getting classCastException but when i cross check the java class name and object retrived from the table's class name both are same Your question is non-specific.
But as a guess from what is implied in the above...you are using class loaders and you are trying to use class from different class loaders as though they are the same class.
That is not the case.
And as stated this problem has nothing to do with JDBC.