users@glassfish.java.net

Re: Same app twice using JPA

From: Sahoo <sahoo_at_sun.com>
Date: Fri, 22 Jun 2007 21:59:42 +0530

Yes, TopLink is definitely mixing things up. See issue 3235 [1] where
this exact problem is discussed recently. As you pointed out, closing
the emf during undeployment won;t avoid the class linking issue. I was
thinking that you actually deploy the same app (with same war/ear name)
twice.

In any case, you should add the code that closes the emf - that makes it
a better app.

Thanks,
Sahoo

[1] https://glassfish.dev.java.net/issues/show_bug.cgi?id=3235

Edson Carlos Ericksson Richter wrote:
> Ok, I'll create a lifecicly listener capable of doing that.
> But I don't see how this could make difference for my
> ClassCastException problem.
>
> Step by step:
>
> 1) Create an application that uses JPA
> 2) Build the WAR distro, and make two copies: MyApp1.war, MyApp2.war
> 3) Edit MyApp1.war and modify persistence.xml to point do DB1. PU name
> stay "MyAppPU".
> 4) Edit MyApp2.war and modify persistence.xml to point do DB2. PU name
> stay "MyAppPU".
> 5) Deploy MyApp1
> 6) Deploy MyApp2
> 7) Access MyApp1, everything works fine. Objects
> info.everest.entities.Customer are loaded from DB1 and HTML table full
> of data is shown.
> 8) Access MyApp2. Exception is thrown: ClassCastException on
> info.everest.entities.Customer.
>
> So, to me appear being:
> a) Problem related to single JVM and two apps with same PU name -
> TopLink (or JPA) is mixing things;
> b) A cache problem, since both applications use same class
> (info.everest.entities.Customer) - probable a TopLink issue.
>
>
> I expect this help a little...
>
> Regards,
>
>
> Edson Richter
>
>
>
> Sahoo escreveu:
>> Hi Edson Richter,
>>
>> TopLink maintains a map of PU names to EMF (this is actually a bug in
>> the current implementation). This map is global for all the
>> applications in the JVM, because TopLink is loaded by a class loader
>> which is the parent of all application class loaders. You are
>> probably *not* closing the EMF when the app gets undeployed. So, when
>> the app is re-deployed, the old EMF is used. Try doing emf.close() in
>> the code that gets called when the app is undeployed. The
>> relationship between undeployment and redeployment is that an app
>> first gets undeployed when it is redeployed. You should be able to
>> find some hooks in the app which gets called during undeployment.
>>
>> Thanks,
>> Sahoo
>>
>> Edson Carlos Ericksson Richter wrote:
>>>
>>>> Why can't you have 2 different PU names in 2 different
>>>> persistence.xml files (that reference the same Entities - this
>>>> shouldn't be the problem)?
>>>>
>>>> thanks,
>>>> -marina
>>> Actually, I don't have 2 different persistence.xml... It's only 1
>>> app being deployied twice - only connection setting is changed on
>>> final WAR, just before deployment (much like if I open the WAR with
>>> WinZip, edit Persistence.xml to set new connection settings, then
>>> update WAR).
>>>
>>>
>>> Regards,
>>>
>>> Edson Richter
>>>
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