Eric,

  Terracotta is using "named classloaders" to assign identity to 
arbitrary class loaders in JVM, so it could tell what classloader been 
used to load each class. I don't think it is related to the issue 
classwords trying to solve.

  regards,
  Eugene


Eric Redmond wrote:
> If you are looking for a mature, full-featured named classloader (and 
> more), consider Classworlds. It used to be here, where you can read a 
> little about it:
>
> http://classworlds.codehaus.org/ <http://classworlds.codehaus.org/>
>
> but is now buried into the core of Plexus... but can still be used as 
> a stand-alone project.
>
> Eric
>
> On 5/22/07, *Steven Harris* < [EMAIL PROTECTED] 
> <mailto:[EMAIL PROTECTED]>> wrote:
>
>
>
>
>     Cheers,
>     Steven Harris
>
>     Director of Engineering
>     [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
>     www.terracotta.org <http://www.terracotta.org>
>
>
>
>     On May 22, 2007, at 3:04 PM, Geert Bevin wrote:
>
>>>     Good question. If someone were to serialize that graph and
>>>     de-serialize it.
>>>     Is that case handled?
>>
>>     Afaik, this isn't automatically handled through serialization.
>>
>>
>>>     If it isn't, can we at least cover a wider subset of the world
>>>     without naming classloaders?
>>>     With web apps for instance? If not, what we would need to make
>>>     things simpler.
>>
>>     I sort of fear that this might be something that is different on
>>     a case-by-case basis. Very dependent on the applications and
>>     frameworks.
>
>     I'll bet we can come up with some default mode that handles a nice
>     swath of the world and then rely on named classloaders for the rest.
>     but that is just a theory at this point. 
>
>
>>
>>>     Would be nice to be able to alias classloader names in config to
>>>     make it easier to share
>>>     objects between say tomcat and a swing app?
>>
>>     I agree that this could be nice, but wouldn't it make the whole
>>     thing even more complex, ie. another concept to understand:
>>     "aliased named classloaders"?
>
>     For the people who need this the only other option is to do it
>     manually which is a big pain. For everyone else, they would never
>     know the concept exists.
>
>     Just being able to make classloader names equivalent between nodes
>     would remove a whole bunch of ugly code in cross appserver and
>     cross classloader
>     architecture worlds. We should probably pick some use cases. i.e .
>     osgi, tomcat to swing, etc. Look at them one at a time and figure
>     out how to best balance
>     out form over function.
>
>>
>>>
>>>
>>>     Cheers,
>>>     Steven Harris
>>>
>>>     Director of Engineering
>>>     [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
>>>     www.terracotta.org <http://www.terracotta.org>
>>>
>>>
>>>
>>>     On May 22, 2007, at 2:52 PM, Geert Bevin wrote:
>>>
>>>>     1. object X instantiates an object Y by loading the class
>>>>     explicitly through another classloader
>>>>     2. object Y is stored into object Z
>>>>     3. object Z is shared
>>>>
>>>>     How can object Z on another node know which classloader has to
>>>>     be used for object Y's class?
>>>>
>>>>     On 22 May 2007, at 23:48, Steven Harris wrote:
>>>>
>>>>>     I believe so. Question in my mind is, why can't we do the same.
>>>>>
>>>>>
>>>>>     Cheers,
>>>>>     Steven Harris
>>>>>
>>>>>     Director of Engineering
>>>>>     [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
>>>>>     www.terracotta.org <http://www.terracotta.org>
>>>>>
>>>>>
>>>>>
>>>>>     On May 22, 2007, at 2:46 PM, Geert Bevin wrote:
>>>>>
>>>>>>     Doesn't serialization just use the caller's current classloader?
>>>>>>
>>>>>>     On 22 May 2007, at 23:42, Steven Harris wrote:
>>>>>>
>>>>>>>     I think we can follow the same rules that serialization follow
>>>>>>>     about choosing classloaders but I'm not sure.
>>>>>>>
>>>>>>>     Cheers,
>>>>>>>     Steven Harris
>>>>>>>
>>>>>>>     Director of Engineering
>>>>>>>     [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
>>>>>>>     www.terracotta.org <http://www.terracotta.org>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>     On May 22, 2007, at 2:38 PM, Geert Bevin wrote:
>>>>>>>
>>>>>>>>     What about classes that are loaded through another classloader
>>>>>>>>     (ie. an application having several classloaders). How well
>>>>>>>>     TC be
>>>>>>>>     able to automatically tell which classloader it has to
>>>>>>>>     retrieve it
>>>>>>>>     from, if it isn't named?
>>>>>>>>
>>>>>>>>     On 22 May 2007, at 23:22, Steven Harris wrote:
>>>>>>>>
>>>>>>>>>     This is something that has come up a few times over the
>>>>>>>>>     last few
>>>>>>>>>     years. Alex mentioned a solution and gkeim mentioned a similar
>>>>>>>>>     solution.
>>>>>>>>>     I want to schedule a brain storming session on it in the
>>>>>>>>>     coming
>>>>>>>>>     weeks
>>>>>>>>>     but...
>>>>>>>>>
>>>>>>>>>     Since I don't believe we ever push objects to a client
>>>>>>>>>     anymore, at
>>>>>>>>>     least not all the way to instantiation, I believe we can
>>>>>>>>>     just use
>>>>>>>>>     the
>>>>>>>>>     classloader of requesting client. This may not
>>>>>>>>>     have always been true but I think it is true now. What reasons
>>>>>>>>>     can we
>>>>>>>>>     think of that would require us to need named classloaders
>>>>>>>>>     anymore?
>>
>>     --
>>     Geert Bevin
>>     Terracotta - http://www.terracotta.org <http://www.terracotta.org>
>>     Uwyn "Use what you need" - http://uwyn.com
>>     RIFE Java application framework - http://rifers.org
>>     Music and words - http://gbevin.com
>>
>>
>
>
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>
>
>
> -- 
> Eric Redmond
> http://www.sonatype.com
> ------------------------------------------------------------------------
>
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>   

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