[news.eclipse.rt.eclipselink] Unknown entity type

[Serge <SergeyExt@xxxxxxxxx>]

Hi,

I have an application with added derby.jar, added eclipselink.jar and 
javax.persistence.jar from eclipse eclipselink-2.0.0.v20090731-r4765 
installtion zip.
I have entity class and some usage of this class and got different ind 
of message when try to use it like:
Exception in thread "main" java.lang.IllegalArgumentException: An 
exception occurred while creating a query in EntityManager:
Exception Description: Error compiling the query [select object(o) from 
DiscountCode as o]. Unknown entity type [DiscountCode].
///
Caused by: Exception [EclipseLink-8034] (Eclipse Persistence Services - 
2.0.0.v20090731-r4765): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Error compiling the query [select object(o) from 
DiscountCode as o]. Unknown entity type [DiscountCode].
///

sometimes (may be with different version of eclipselink I have also 
message about missed "@Entity annotation"

What may be wrong?



////////////////////////

my persistence.xml:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 
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";>
  <persistence-unit name="JavaApplication8PU" 
transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>javaapplication8.DiscountCode</class>
    <properties>
      <property name="javax.persistence.jdbc.url" 
value="jdbc:derby://localhost:1527/sample"/>
      <property name="javax.persistence.jdbc.password" value="app"/>
      <property name="javax.persistence.jdbc.driver" 
value="org.apache.derby.jdbc.ClientDriver"/>
      <property name="javax.persistence.jdbc.user" value="app"/>
    </properties>
  </persistence-unit>
</persistence>

my entity:
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package javaapplication8;

import java.io.Serializable;
import java.math.BigDecimal;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

/**
 *
 * @author sp153251
 */
@Entity
@Table(name = "DISCOUNT_CODE")
@NamedQueries({@NamedQuery(name = "DiscountCode.findAll", query = 
"SELECT d FROM DiscountCode d"), @NamedQuery(name = 
"DiscountCode.findByDiscountCode", query = "SELECT d FROM DiscountCode d 
WHERE d.discountCode = :discountCode"), @NamedQuery(name = 
"DiscountCode.findByRate", query = "SELECT d FROM DiscountCode d WHERE 
d.rate = :rate")})
public class DiscountCode implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @Column(name = "DISCOUNT_CODE")
    private Character discountCode;
    @Column(name = "RATE")
    private BigDecimal rate;

    public DiscountCode() {
    }

    public DiscountCode(Character discountCode) {
        this.discountCode = discountCode;
    }

    public Character getDiscountCode() {
        return discountCode;
    }

    public void setDiscountCode(Character discountCode) {
        this.discountCode = discountCode;
    }

    public BigDecimal getRate() {
        return rate;
    }

    public void setRate(BigDecimal rate) {
        this.rate = rate;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (discountCode != null ? discountCode.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id 
fields are not set
        if (!(object instanceof DiscountCode)) {
            return false;
        }
        DiscountCode other = (DiscountCode) object;
        if ((this.discountCode == null && other.discountCode != null) 
|| (this.discountCode != null && 
!this.discountCode.equals(other.discountCode))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "javaapplication8.DiscountCode[discountCode=" + 
discountCode + "]";
    }

}