Can not set java.lang.Integer field Xyz.id to Xyz - IllegalArgumentException

[zemunk]

Hello,

I came across this error while trying to persist some values. Since I am new to the technology and the project was developed by someone else, I have difficulties in finding the source of the problem.

Here is the entity class:

    @Entity
    @Table(schema = "webshop_statistik", name = "adressStatistik")
    @SequenceGenerator(name = "adressStatistik_id_seq", sequenceName = "webshop_statistik.adressstatistik_id_seq")
    public class AdressStatistik {
        /**
         * automatisch vortlaufend erzeugter Primary Key
         */
        @Id
        @GeneratedValue(generator = "adressStatistik_id_seq")
        private Integer id;
        @Column(length = 50)
        private String ort;
        ...    
        public Integer getId() {
            return id;
        }
        public void setId(Integer id) {
            this.id = id;
        }
        public String getOrt() {
            return ort;
        }
        public void setOrt (String ort) {
            this.ort = ort;
        }
        ...
    }

and the calling method:

@Stateless
@WebService
@WebContext(authMethod="BASIC", secureWSDLAccess=false)
@SecurityDomain("gfo")
@RolesAllowed({"webshop"})
public class Statistikmgmt implements IStatistikmgmt {
    @PersistenceContext(unitName="gfo_pu")
    private EntityManager em;
     ...    
    @SuppressWarnings({ "unchecked"})
    @WebMethod
    @Override
    public void persistAdressStatistik(@WebParam(name="adressStatistik")AdressStatistik a){
               ...
                em.persist(a); // the exception is thrown here
               ...
    }
}

I get the same error for other beans as well. Here is a part of the error log:

13:24:12,311 ERROR [org.jboss.ejb3.invocation] (http-localhost-127.0.0.1-8080-6) JBAS014134: EJB Invocation failed on component Statistikmgmt for method public void de.intern.webservices.Statistikmgmt.persistAdressStatistik(de.webshop_statistik.bean.entity.AdressStatistik): javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.webshop_statistik.bean.entity.AdressStatistik.id

...

13:24:12,372 ERROR [org.jboss.as.webservices.invocation.InvocationHandlerEJB3] (http-localhost-127.0.0.1-8080-6) Method invocation failed with exception: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.webshop_statistik.bean.entity.AdressStatistik.id: javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.webshop_statistik.bean.entity.AdressStatistik.id

...

13:24:12,431 WARNUNG [org.apache.cxf.phase.PhaseInterceptorChain] (http-localhost-127.0.0.1-8080-6) Application {http://webservices.intern.de/}StatistikmgmtService#{http://webservices.intern.de/}persistAdressStatistik has thrown exception, unwinding now: org.apache.cxf.interceptor.Fault: javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of de.webshop_statistik.bean.entity.AdressStatistik.id

...

...

Caused by: java.lang.IllegalArgumentException: Can not set java.lang.Integer field de.webshop_statistik.bean.entity.AdressStatistik.id to de.webshop_statistik.bean.entity.AdressStatistik

The project is already working under Jboss 5 and is now in the process of being deployed to Jboss 7.1.

Thank you for helping me out!