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From Daniel John Debrunner <...@debrunners.com>
Subject Re: [jira] Created: (DERBY-556) NetworkServer does not set thread context classloader
Date Tue, 06 Sep 2005 20:45:35 GMT
Jeremy Boynes wrote:


> 
>> Is there some concrete example you have that is broken?
>>
> 
> In Geronimo we use Derby as the system database, use a J2CA RAR file to
> define Resource that can be used to access; that RAR file binds the
> embedded driver to a DataSource and also starts a NetworkServer to allow
> access to database from clients.
> 
> To allow users to define other J2CA RARs that access the same engine, we
> needed to place the engine code in the appserver's classloader; if we
> don't, then the second RAR fails to open the database as access is being
> attempted from two different classloaders.
> 
> Unfortunately we do have a second RAR which includes some stored
> procedures and which defines a NetworkServer. This works fine for in-VM
> applications as they connect through the embedded driver which so the
> procedure classes are found using the TCCL. However, clients that access
> the server via this NetworkServer cannot see the procedure classes
> because they are not in the appserver's classloader. If the
> NetworkServer copied the TCCL from the RAR that started it onto its
> worker threads then the engine would be able to load those procedure
> classes.

Thanks for the explanation.
> 
> I am thinking of addressing this by allowing a ClassLoader to be passed
> to the NetworkServer when it is created. This would then set as the TCCL
> for any worker threads it creates.

Could the network server do this automatically? If the thread that
starts it has a TCCL, then it uses that for all worker threads?

Dan.




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