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Message-ID: <4F0CE261.1010305@christopherschultz.net>
Date: Tue, 10 Jan 2012 20:14:09 -0500
From: Christopher Schultz <chris@christopherschultz.net>
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To: Tomcat Developers List <dev@tomcat.apache.org>
Subject: Re: More Caching for WebappClassLoader?
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 <4F0CA7A3.5070000@christopherschultz.net> <4F0CBDC7.4000006@kippdata.de>
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Rainer,

On 1/10/12 5:37 PM, Rainer Jung wrote:
> It would matter if they take the reedom to return something new if
> loadClass() is called for a class that was already loaded - and
> something changed for the CL. For example a custom CL could check every=

> now and then whether the classes have dynamically changed and then
> return the new ones. If we cache the first result of loadClass() in our=

> loader higher up the hierarchy, the custom CL lower down will never be
> called again for the class and wouldn't be able to update it.

I'm not sure why a custom CL would be "lower" in the hierarchy than the
WebappClassLoader but then also not have first-crack at loading the
classes it had originally loaded. If the CL follows parent-first
semantics then this might be a problem, but if the CL follows me-first
semantics, then this will not be a problem.

> Right, that's what I wanted to say. So at the end it might be a few
> thousands of pointers.

Yeah, that's not that big of a deal when the alternative is what amounts
to CL thrashing :)

-chris


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