NameNotFoundException in Container Managed EntityManager - jpa

Question

I am trying to use Container Managed EntityManager, however I am getting NameNotFoundException. I have tried adding entries in web.xml but in vain.
#Stateless
#Path("/mypath")
public class EmployeeService {
#EJB
private EmployeeDAO employeeDAO;
#GET
#Path("/myresults")
#Produces(MediaType.APPLICATION_JSON)
public Employee getValues() {
Employee emp = new Employee();
try {
emp = employeeDAO.getEmployees(); // exception here
} catch (Exception ex) {
ex.printStackTrace();
}
return emp;
}
EmployeeDAO code snippet
public class EmployeeDAO {
#PersistenceContext(unitName = "test-ejb", name = "persistence/em")
public Employee getEmployees() throws NamingException {
int empNo = 342;
Context context = new InitialContext();
context.lookup("java:comp/env");
EntityManager em = (EntityManager)context.lookup("persistence/em");
return em.find(Employee.class, empNo);
}
persistence.xml
<?xml version="1.0" encoding="UTF-8" ?>
<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_1_0.xsd" version="1.0"
xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="test-ejb" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/testDS</jta-data-source>
<class>test.entity.Employees</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="eclipselink.target-server" value="OC4J"/>
<property name="javax.persistence.target-database" value="Oracle"/>
<property name="javax.persistence.logging.parameters" value="TRUE"/>
</properties>
</persistence-unit>
</persistence>
Exception stack
javax.naming.NameNotFoundException: persistence/em not found
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.rmi.RMIServerContext.lookup(RMIServerContext.java:207)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.ApplicationContext.unprivileged_lookup(ApplicationContext.java:256)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.ApplicationContext.lookup(ApplicationContext.java:196)
at javax.naming.InitialContext.lookup(InitialContext.java:392)
at test.dao.EmployeeDAO.getValues(EmployeeDAO.java:39)
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)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:734)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:391)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.HttpRequestHandler.doProcessRequest(HttpRequestHandler.java:908)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:458)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.HttpRequestHandler.serveOneRequest(HttpRequestHandler.java:226)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.HttpRequestHandler.run(HttpRequestHandler.java:127)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].server.http.HttpRequestHandler.run(HttpRequestHandler.java:116)
at oracle.oc4j.network.ServerSocketReadHandler$SafeRunnable.run(ServerSocketReadHandler.java:260)
at com.evermind[Oracle Containers for J2EE 10g (10.1.3.5.0) ].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:303)
at java.lang.Thread.run(Thread.java:662)
Update 1
#Stateless
#LocalBean
public class EmployeeDAO {
#PersistenceContext(unitName = "test-ejb", name = "persistence/em")
public Employee getEmployees() throws NamingException {
int empNo = 342;
Context context = new InitialContext();
context.lookup("java:comp/env");
EntityManager em = (EntityManager)context.lookup("persistence/em");
return em.find(Employee.class, empNo);
}
Exception
javax.ejb.EJBException: Setter injection being applied to non-setter method: getValues; nested exception is: java.lang.InstantiationException: Setter injection being applied to non-setter method: getValues
Full stack
Caused by: java.lang.InstantiationException: Setter injection being applied to non-setter method: getValues
at com.evermind.server.deployment.J2EEContextAnnotationParser.validateInjectionSetter(J2EEContextAnnotationParser.java:713)
at com.evermind.server.deployment.J2EEContextAnnotationParser.createInjectionTarget(J2EEContextAnnotationParser.java:729)
at com.evermind.server.deployment.J2EEContextAnnotationParser.parseInjectedMethod(J2EEContextAnnotationParser.java:378)
at com.evermind.server.ejb.deployment.BeanDescriptorAnnotationParser.parseInjectedMethodAndCallbacks(BeanDescriptorAnnotationParser.java:276)
at com.evermind.server.ejb.deployment.SessionBeanDescriptorAnnotationParser.parseInjectedMethodAndCallbacks(SessionBeanDescriptorAnnotationParser.java:95)
at com.evermind.server.ejb.deployment.BeanDescriptorAnnotationParser.parseAnnotations(BeanDescriptorAnnotationParser.java:77)
at com.evermind.server.ejb.deployment.BeanDescriptorAnnotationParser.parseAnnotations(BeanDescriptorAnnotationParser.java:48)
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)
at com.evermind.server.ejb.BeanAnnotationListener.parseAnnotatedClass(BeanAnnotationListener.java:45)

Answer 1

Change:
public class EmployeeDAO {
#PersistenceContext(unitName = "test-ejb", name = "persistence/em")
...
to:
#PersistenceContext(unitName = "test-ejb", name = "persistence/em")
#Stateless
public class EmployeeDAO {
...

Answer 2

EmployeeDAO must be a container-managed class (listener, filter, servlet, EJB, managed bean, CDI managed bean, etc.), not a POJO. The JPA container will only search for JPA annotations on container-managed classes, not on POJOs.
Your options are:
Change EmployeeDAO to be a container-managed class. For example, if your application server supports EJBs, then add the #Stateless annotation to the class.
Move the #PersistenceContext annotation to a container-managed class. For example, if you have an existing listener, filter, or servlet, move the annotation to that class.
Add <persistence-context-ref> to web.xml.
Note, your application server must support container-managed JPA for any of these approaches to work.