Error Adding object to collection

Question

Hi all... I'm using Toplink + ADF Faces...
We have the following problem: There are 2 tables involved, table A and table B
Table B has a FK to table A, therefore a one-to-one mapping from B to A and a one to many mapping (collection) from A to B.
What I want to do is to add an object of type B to the collection of an A object. I'm showing an input form for the constructor of type B, a submit button, and a read only table bellow to show the items of the collection. I have done this several times and worked fine, now I have NO clue why this is not working.
What I used to do to achieve this is to call the method of the type A "addB(B)" (to add the object) and then the "Execute" operation (to refresh the table shown) of the collection in which the addB method is adding objects.
What I get is just:
2006-11-17 13:53:30.421 WARNING JBO-29000: Unexpected exception caught: java.lang.NullPointerException, msg=null
2006-11-17 13:53:30.421 WARNING java.lang.NullPointerException
and no more details.... :-S
Does anyone know why this could be happening???
or
Is there some other way of adding objects to a collection using ADF and toplink?? Any suggestion is more than welcome!! I've been trying for too long to solve this... :-(
Thanks in advance

Answer 1

Here is another symptom:
a few days ago, I developed a search page of objects of type "C". This type, has a collection of objects of type "B". This page is working fine, now... I do exactly the same steps to create a new page with the same search functionallity, and I get the same NullPointerException described above (with no extra information).
Since the development of that working page until now, I manually added the mapping of table "A", which was not mapped by the time we developed the working search page. So I guess something is wrong with this new mapping.
Here are the steps i did to map the new table "A" and define the relationship with table B (through a foreing key defined in DB):
- created Java objects from tables for table "A".
- added a FK from "B"->"A" in table "B" in the Offline Database Sources (just like the FK in the real DB)
- added a ValueHolder attribute to class "B" (with the appropiate get and set, and initializing it in the constructor of class "B")
- added a List attribute in class "A" of objects of type "B" (with the appropiates add, remove, get and set methods), and initializing the List as a new ArrayList in the constructor.
- in the toplink map, mapped the new attributes:
one-to-one for the Valueholder in class "B" (using the appropiate FK)
one-to-many for the List attributes in class "A" (using the appropiate FK)
- refreshed all possible datacontrol
And thats it... am I doing something wrong or missing something??
Is there any other way to map a new table into an existing toplink mapping? I'm using Jdev 10.1.3 Integrated workbench...
I will really appreciate any suggestion or comment, I really have no clue why this is happening.... Thanks in advance