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http://issues.apache.org/jira/browse/DERBY-556?page=comments#action_12357763 ]
Jeremy Boynes commented on DERBY-556:
-------------------------------------
This problem will not manifest if the procedure classes are on the system
classpath (${CLASSPATH}) - you need to be playing tricks with classloaders,
hence the relation to GERONIMO-1001 :-)
Assume that MathUtils.jar is not on the system classpath but is on the
classpath for a user defined classloader CL. If you set the Thread's context
classloader (TCCL) to be CL and then connect to Derby using an embedded
connection, the procedure classes will successfully be loaded from CL.
However, if you then start a network server (with CL as TCCL), worker threads
created by the network server do not have the TCCL thread set and hence the
procedure classes will not be found. This was where the problem manifested in
Geronimo as the application classes were present in a RAR (with CL being the
RAR's classloader) but the Derby engine was present in a parent classloader
(the appserver's).
I think a safe fix for this is for the network server to set the TCCL of its
worker threads either to some classloader explictly set as a parameter during
startup or to the TCCL in place when it is started.
There is no issue with classes being loaded if the classloader is defined using
derby.database.classpath
If that makes sense, let me know; if not, I will try and put together an
explicit testcase. I did look at fixing this but ran into issues with how the
network server was being started by some of the monitor code and then
backburnered this issue when we had the workaround using
derby.database.classpath
> NetworkServer does not set thread context classloader
> -----------------------------------------------------
>
> Key: DERBY-556
> URL: http://issues.apache.org/jira/browse/DERBY-556
> Project: Derby
> Type: Bug
> Components: Network Server
> Versions: 10.1.1.0
> Reporter: Jeremy Boynes
> Assignee: Rick Hillegas
> Attachments: MathUtils.jar, z.sql, zz.sql
>
> The NetworkServer does not set the thread context classloader which is used
> to load the implementations of stored procedures. As a result, procedure
> implementations must be present in the classpath of the engine itself; this
> differs from embedded mode where classes may be located in the application.
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