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