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From "David Van Couvering (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-1075) Combine the script and the test available for upgrade testing into a java test
Date Wed, 22 Mar 2006 00:13:59 GMT
    [ http://issues.apache.org/jira/browse/DERBY-1075?page=comments#action_12371362 ] 

David Van Couvering commented on DERBY-1075:
--------------------------------------------

This is a very common misunderstanding of setContextClassLoader, and one that has thrown many
of us, including myself, for quite a loop.  It turns out that setContextClassLoader() is of
*absolutely no use* unless someone later on in the same thread decides to grab it using getContextClassLoader()
and use it.  It appears to be most commonly used by application servers, who want to use a
separate classloader for each thread.

That said, it is worth noting that org.apache.derby.impl.services.reflect.ReflectClassesJava2
appears to use getContextClassLoader.  It appears to be used to load classes that are not
in derby.jar (e.g. application classes), I *think* if the class can't be found by the default
classloader.   I'm not sure if this is the right thing to do, but this is what it does.  You
might just try not setting the context classloader and see what happens, but I guess if you
want to be safe you might as well go and set it.

But you're right, the way to get a class to use a specific classloader as its *default* classloader
(which is *different* from the context classloader) is to use Class.forName() or otherwise
explicitly load that class using the classloader you want.  Then whenever it does "new" it
uses that classloader.

I'll attach the code, once I find it.

> Combine the script and the test available for upgrade testing into a java test
> ------------------------------------------------------------------------------
>
>          Key: DERBY-1075
>          URL: http://issues.apache.org/jira/browse/DERBY-1075
>      Project: Derby
>         Type: Sub-task
>     Reporter: Deepa Remesh
>     Assignee: Deepa Remesh
>     Priority: Minor
>      Fix For: 10.2.0.0
>  Attachments: derby-1075-patch1-draft.diff, derby-1075-patch1-draft.status, derby-1075-v1.diff,
derby-1075-v1.status, loader.java, loader_v2.java
>
> Separating a part of DERBY-514 into a sub-task. This sub-task is to combine the script
'runphases.ksh' and the java file 'phaseTester.java' into a single java test. This will help
to later add the upgrade tests into the regression suite. Also, this sub-task can be done
independent of DERBY-1049 which is blocking DERBY-514.

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