EntityManager not getting injected in EJB, resulting in NullPointerException

[Shilpa Mishra]

am new to J2EE and have been trying to resolve this issue from almost a week. This is the code in my session bean where in I am getting a NullPointerException. Found out that the entity manager is not getting injected. Can anyone pllllzzzz lemme know how to resolve it.

The code from session bean:

package session;
import entity.User;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Stateless
public class UserFacade extends AbstractFacade<User> {
    @PersistenceContext (unitName = "EXAMPU")
    private EntityManager em;

    @Override
    protected EntityManager getEntityManager() {
          return em;
    }

    public UserFacade() {
          super(User.class);
    }

    public String validateUser(String username, String password) {
         System.out.println("in facade");    
         boolean pwdMatch = false;

         System.out.println("in UserInfoFacade validate " + em);
    try {
              System.out.println("username " + username);
              System.out.println("password " + password);
 
             if(em == null) {
                       System.out.println("em is null");
              }
              else {
                    System.out.println("em is not null");
              }

              List results = em.createNamedQuery("User.findByUserName").setParameter("userName", username).getResultList();

               System.out.println("Entity manger is open " + em.isOpen());

              if (!results.isEmpty())
             {

                    Iterator userList = results.iterator();
                    while (userList.hasNext())
                    {
                          User user = (User) userList.next();
                          if (user != null)
                          {
                                  if (user.getPassword().equals(password))
                                 {
                                          pwdMatch = true;
                                 }
                                 else {
                                            pwdMatch = false;
                                  }
                            }
                        else {
                                    return "NULL";
                          }
             }
            if (pwdMatch) {
                      return "MATCH";
            }
            else {
                    return "NO_MATCH";
            }
        }
        else {
                 return "NOT_FOUND";
        }
    } catch (Exception ex) {
        //ex.printStackTrace();
        System.out.println("Caught exception in UserFacade " + ex.toString());
    }
             return "NULL";
    }


}


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="EXAMPU" transaction-type="JTA">
      <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> 
      <jta-data-source>EXAM</jta-data-source>

    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties/>
  </persistence-unit>
</persistence>

Thanks in advance

[Ranganathan Kaliyur Mannar]

Hi,
Please UseCodeTags when posting code. Click on the link to understand how to do that.

You have indicated you have a NullPointerException. Please provide the stack trace as that would point to the line where this happens: TellTheDetails.

[Shilpa Mishra]

Hi,
Sorry am new to the forum, added the code tags.
This is the last 2 lines from the stack trace.
SEVERE: java.lang.NullPointerException
at session.UserFacade.validateUser(UserFacade.java:56)
I am getting the Null Pointer Exception in this line

List results = em.createNamedQuery("User.findByUserName").setParameter("userName", username).getResultList();

From the msgs that I have printed out, it shows that em is null.
Could you please lemme know what am I missing

Thanks,

Ranganathan Kaliyur Mannar wrote:Hi,
Please UseCodeTags when posting code. Click on the link to understand how to do that.

You have indicated you have a NullPointerException. Please provide the stack trace as that would point to the line where this happens: TellTheDetails.

[Jelle Klap]

To which application server are you deploying, and what does the structure of your deployment look like?

[Shilpa Mishra]

Hey Guys,
Solved it.. Had not injected EJB at managed bean level. Thats where the prob was .

Jelle Klap wrote:To which application server are you deploying, and what does the structure of your deployment look like?