Newbie mistake with annotations - NPE

amallah · **Joined:** Tue Jan 16, 2007 8:43 pm **Posts:** 5

I just converted from programmatic declaration of my EntityManager to annotations in one Session bean. The old (working) code:

Code:

package com.myorg.util;

import com.myorg.company.*;
import com.myorg.util.*;
import javax.persistence.*;

public class PlaceHolder {
   public Company findByPrimaryKey(CompanyPK companyPK) {
      EntityManager em = EJBUtil.getEntityManagerFactory().createEntityManager();
      Company c = (Company) em.find(Company.class, new Integer(companyPK.iD));
      em.close();
      return c;
   }
}

I changed this one file to:

Code:

package com.myorg.util;

import com.myorg.company.*;
import com.myorg.util.*;
import javax.persistence.*;
import javax.ejb.*;

@Stateless
public class PlaceHolder {

   @PersistenceContext(unitName = "myorgPersistence");
   EntityManager em;

   public Company findByPrimaryKey(CompanyPK companyPK) {
      Company c = (Company) em.find(Company.class, new Integer(companyPK.iD));
      return c;
   }
}

Here is my persistence.xml:

Code:

<persistence 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_1_0.xsd"
   version="1.0">

   <persistence-unit name="epmPersistence">
      <provider>org.hibernate.ejb.HibernatePersistence</provider>
      <jta-data-source>hibernate.ds</jta-data-source>
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle9Dialect" />
         <property name="hibernate.transaction.factory_class" value="org.hibernate.transaction.CMTTransactionFactory" />
         <property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.WeblogicTransactionManagerLookup" />
         <property name="showSql" value="true" />
      </properties>
   </persistence-unit>
</persistence>

The exception that is thrown is:

Code:

<DEBUG> 18:06:25,144 org.springframework.web.servlet.DispatcherServlet: Could not complete request
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
Caused by:
java.lang.NullPointerException
        at com.myorg.util.PlaceHolder.findByPrimaryKey(PlaceHolder.java:15)
        at com.myorg.util.jsp.ThemeUtil.load(ThemeUtil.java:121)
        at com.myorg.util.jsp.ThemeUtil.getAllComponents(ThemeUtil.java:164)
        at com.myorg.util.jsp.ThemeUtil.getComponents(ThemeUtil.java:180)
        at com.myorg.util.EPMExceptionResolver.resolveException(EPMExceptionResolver.java:52)
        at org.springframework.web.servlet.DispatcherServlet.processHandlerException(DispatcherServlet.java:1049)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:836)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:755)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:396)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:350)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
        at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:225)
        at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:127)
        at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:283)
        at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175)
        at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:499)
        at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:245)
        at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:142)
        at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:247)
        at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1105)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:841)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:755)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:396)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:350)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
        at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:225)
        at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:127)
        at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:283)
        at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175)
        at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:499)

It appears that the em is null. Am I injecting improperly? Thanks for any advice.

emmanuel · **Posted:** Sun Mar 11, 2007 8:03 pm

the persistence unit names does not match apparently