1 Reply Latest reply on Apr 30, 2008 12:18 PM by Joao Viragine

    Problem with EntityManager

    yannick bardon Newbie

      Hi,


      Here is my problem, I have a class annotated @ Stateless in this class there is a variable EntityManager annotated @ PersistenceContexte.


      Here is the code:



      @Stateless
      @Name("home")
      public class HomeBean implements Home{
              @PersistenceContext
           EntityManager em;
           
           
           public HomeBean(){
                    Query q = em.createQuery("select t from TypeDocument as t");  
                     
                 List<TypeDocument> type = (List<TypeDocument>) q.getResultList();
                     
              }
      }
      





      The problem in the constructor of the class, I use em.createQuery, and here I have is a mistake which is a null pointer exception.
      Here is the error:



      09:41:06,210 ERROR [STDERR] java.lang.NullPointerException
      09:41:06,210 ERROR [STDERR]     at sessionBeans.HomeBean.<init>(HomeBean.java:12
      0)
      09:41:06,210 ERROR [STDERR]     at sun.reflect.NativeConstructorAccessorImpl.new
      Instance0(Native Method)
      09:41:06,210 ERROR [STDERR]     at sun.reflect.NativeConstructorAccessorImpl.new
      Instance(NativeConstructorAccessorImpl.java:39)
      09:41:06,210 ERROR [STDERR]     at sun.reflect.DelegatingConstructorAccessorImpl
      .newInstance(DelegatingConstructorAccessorImpl.java:27)
      09:41:06,210 ERROR [STDERR]     at java.lang.reflect.Constructor.newInstance(Con
      structor.java:494)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.EJBContainer.construct(EJBCont
      ainer.java:511)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.AbstractPool.create(AbstractPo
      ol.java:66)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.ThreadlocalPool.get(Threadloca
      lPool.java:61)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.stateless.StatelessInstanceInt
      erceptor.invoke(StatelessInstanceInterceptor.java:54)
      09:41:06,210 ERROR [STDERR]     at org.jboss.aop.joinpoint.MethodInvocation.invo
      keNext(MethodInvocation.java:101)
      09:41:06,210 ERROR [STDERR]     at org.jboss.aspects.security.AuthenticationInte
      rceptor.invoke(AuthenticationInterceptor.java:77)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.security.Ejb3AuthenticationInt
      erceptor.invoke(Ejb3AuthenticationInterceptor.java:106)
      09:41:06,210 ERROR [STDERR]     at org.jboss.aop.joinpoint.MethodInvocation.invo
      keNext(MethodInvocation.java:101)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.ENCPropagationInterceptor.invo
      ke(ENCPropagationInterceptor.java:46)
      09:41:06,210 ERROR [STDERR]     at org.jboss.aop.joinpoint.MethodInvocation.invo
      keNext(MethodInvocation.java:101)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.asynchronous.AsynchronousInter
      ceptor.invoke(AsynchronousInterceptor.java:106)
      09:41:06,210 ERROR [STDERR]     at org.jboss.aop.joinpoint.MethodInvocation.invo
      keNext(MethodInvocation.java:101)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.stateless.StatelessContainer.l
      ocalInvoke(StatelessContainer.java:214)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.stateless.StatelessContainer.l
      ocalInvoke(StatelessContainer.java:184)
      09:41:06,210 ERROR [STDERR]     at org.jboss.ejb3.stateless.StatelessLocalProxy.
      invoke(StatelessLocalProxy.java:81)
      09:41:06,210 ERROR [STDERR]     at $Proxy150.getFiltreNom(Unknown Source)
      09:41:06,210 ERROR [STDERR]     at sun.reflect.NativeMethodAccessorImpl.invoke0(
      Native Method)
      



      How do I solve the problem?


      Thank you