JPA静态编织抛出异常

Question

为了提高我的应用程序的性能，我尝试使用静态编织。我用eclipelink / tomcat。

访问我的服务时出现以下错误：

java.lang.NullPointerException
    at java.lang.Class.isAssignableFrom(Native Method)
    at org.eclipse.persistence.mappings.ForeignReferenceMapping.preInitialize(ForeignReferenceMapping.java:809)
    at org.eclipse.persistence.mappings.ObjectReferenceMapping.preInitialize(ObjectReferenceMapping.java:940)
    at org.eclipse.persistence.descriptors.ClassDescriptor.preInitialize(ClassDescriptor.java:3320)
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.initializeDescriptors(DatabaseSessionImpl.java:429)
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.initializeDescriptors(DatabaseSessionImpl.java:406)
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.postConnectDatasource(DatabaseSessionImpl.java:671)
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.login(DatabaseSessionImpl.java:633)
    at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:230)
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:369)
    at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:151)
    at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:207)
    at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:195)
    at org.employee.resources.DeptResource.getAllDepts(DeptResource.java:102)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)

我不确定我做错了什么。有人可以帮助我吗？

感谢您的帮助

修改

@Path("/employees")

public class DeptResource {

private EntityManagerFactory factory;
private EntityManager mgr;

@GET
@Produces({MediaType.APPLICATION_XML})
public List<Dept> getAllDepts(){

try
{
    factory = Persistence.createEntityManagerFactory("employeeModel");
    mgr = factory.createEntityManager();
}
catch (Exception e)
{
    throw new Exception("..............");
}

List<Dept> deptResponseList = new ArrayList<Dept>();    

try {

        TypedQuery<Dept> query = mgr.createQuery("SELECT d FROM Department d", Dept.class);
        Collection<Dept> deptList = query.getResultList();
        Iterator<Dept> i = deptList.iterator();

        while (i.hasNext())
        {
            Department response = new Department();

            Dept dept = (Dept) i.next();

            response.setDeptCode(dept.getDeptCode());
            response.setDeptDesc(dept.getDeptDesc());
            response.setDeptURL("URL got from another source using another web service");
            deptResponseList.add(response);
        }
 } catch (NoResultException ex) {
        mgr.close();
        factory.close();
      throw new Exception("------");
 }

        mgr.close();
        factory.close();

 return deptResponseList; 
}