Re: Strange "ClassCast" Exception (and even stranger way it disappear)

[Andrei Tchijov <an...@tchijov.com>]

I have stopped my application, opened mysql and used "UPDATE ..." to  
set appropriate columns to "null".

I do have "@ManyToOne" defined like this

	@ManyToOne
	private PLSObject 					object;
	


On Mar 17, 2009, at 10:50 , Michael Dick wrote:

> Hi Andrei
>
> What do you mean by reseting the version field to null?
>
> The application should not update the version field (nor should it  
> need to).
> OpenJPA will update the version for you automatically, if the  
> application is
> calling setVersion(1) then that could cause problems. Off the top of  
> my head
> I don't think it would manifest as a ClassCastException though.
>
> Do you have the corresponding @ManyToOne annotation on  
> PLSRelationship?
>
> -mike
>
>
> On Tue, Mar 17, 2009 at 7:45 AM, Andrei Tchijov <an...@tchijov.com>  
> wrote:
>
>>
>> Out of blue, I started to get following exception:
>> http://n2.nabble.com/file/n2491173/ClassCastException.txt
>> ClassCastException.txt .
>>
>> To the best of my understanding, problem occur when I am trying to  
>> access
>> @OneToMany field defined as following:
>>
>>       @OneToMany(     mappedBy = "object", cascade = ALL  )
>>       @MapKey(name = "name")
>>       private Map<String,PLSRelationship> relationships;
>>
>>
>> What was particularly weird, I have quite a few objects in the data  
>> base
>> and
>> this exception was happening only when I was trying to access  
>> particular 2
>> of these objects.  It was quite persistent too.  It always was  
>> happening
>> when I was trying to access these 2 particular objects.
>>
>> I was trying to figure out what was so special about these 2  
>> objects and
>> the
>> only thing I could see was that "@Version" field in records  
>> representing
>> one
>> of PLSRelationship "related" to objects which were giving me an  
>> exception
>> were non null ( it was "1" ). On the wimp, I have reset value of all
>> "@Version" fields to null and now it works without any problems.
>>
>> I would greatly appreciate if some one can shade some light on this  
>> issue.
>> Obviously, I am doing something wrong and manage to get my data  
>> base into
>> state which OpenJPA did not like much.  The problem is that I have  
>> no idea
>> what exactly I did wrong (and how to prevent it from happening).
>>
>> You comments will be highly appreciated,
>>
>> Andrei
>>
>> P.S. I am running OpenJPA 1.2.0 with mySQL.  All classes are  
>> enchanted
>> during build time (using ant task).
>> --
>> View this message in context:
>> http://n2.nabble.com/Strange-%22ClassCast%22-Exception-%28and-even-stranger-way-it-disappear%29-tp2491173p2491173.html
>> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>>
>>