0 Replies Latest reply: Mar 18, 2012 7:02 AM by matiger RSS

    Entity-Bean in a Entity-Bean is not working

    matiger Newbie

      Hi,

       

      I just started developing with JBoss AS 7 and EJB and I wasn't sure if I should put this question in the beginners corner. If that would be better, maybe somebody can move it there.

       

      I created an Entity-Bean 'Auction' which contains some String-fields and two fields that contain entities too.

       

      @Named
      @Entity
      public class Auction {
      
          @Id
          @GeneratedValue
          private Long id;
      
          @ManyToOne
          private User creator;
      
          @ManyToOne
          private Town town;
          private String mandatory;
          private String optional;

      // getters and setters...

       

      Now I want to create a new Auction-Bean and persist it, but I always get a NullPointerException.

       

      Here the Frontendcode:

       

                                                    
           <h:selectOneListbox id="name" value="#{newAuction.creator.id}" size="1">
                <f:selectItems var="item" itemLabel="#{item.name}" itemValue="#{item.id}" value="#{userManager.users}" />
           </h:selectOneListbox>
           <h:selectOneListbox id="town" value="#{newAuction.town.id}" size="1">
                <f:selectItems var="item" itemLabel="#{item.name}" itemValue="#{item.id}" value="#{townManager.towns}" />
           </h:selectOneListbox>
           <h:inputText
                id="mandatory"
                value="#{newAuction.mandatory}" />
           <h:inputText
                id="optional"
                value="#{newAuction.optional}" />
           <h:commandButton
                id="register"
                action="#{auctionManager.addAuction()}"
                value="Register" />     

       

      But now I get an Exception like this:

       

      value="#{newAuction.creator.id}": Target Unreachable, 'creator' returned null

       

      I do understand that the field 'creator' is not initialized when I try to set the id, but how do I do it then? I just want to put the Bean that's already initialised (for showing the combo-box) in there.

       

      It's kinda hard to google this stuff, I tried

       

      any help is really appreciated.

       

      Thanks, Mati