Question

I need to detach some entity objects from the database to make them unmanaged. I use EclipseLink persistence provider, which method EntityManager.detach() is exactly one I need. The problem is that JBoss throws at runtime following exception (when execution passes to detach()):

javax.ejb.EJBTransactionRolledbackException: Unexpected Error
java.lang.NoSuchMethodError: javax.persistence.EntityManager.detach(Ljava/lang/Object;)V

Other methods like persist, merge, find work fine. I tried Hibernate and know that its Session provides a special method evict(), which detaches entity, but EclipseLink has no such method.
Example of using detach():

@PersistenceContext(unitName="Course7-ejbPU")
protected EntityManager manager;
(...)
Query query;
List<Message> resultList;
query = manager.createNamedQuery("Message.getUserInputMessageList");
query.setParameter("login", login);
query.setMaxResults(5);
resultList = query.getResultList();
for (Message message : resultList)
    if (message.getContent().length() > 50)
    {
        manager.detach(message);              
        message.setContent(message.getContent().substring(0, 50) + "...");
    }

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="Course7-ejbPU" transaction-type="JTA">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <jta-data-source>java:/Course7ds</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
        <property name="eclipselink.target-server" value="JBoss"/>
    </properties>
  </persistence-unit>
</persistence>

Library with provider data is included into ear archive.
EclipseLink version is 2.2.0 (tested with 2.3.2 – no difference), JBoss server version 5.1.0. Any suggestions will be appreciated.

Answer 1

This exception shows that you’re not using JPA2, but JPA1. You should probably use a more recent version of JBoss, that ships with JPA2.