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From Carsten Ziegeler <cziege...@apache.org>
Subject Re: One more change to be included into the release...
Date Wed, 24 Aug 2005 06:09:12 GMT
Vadim Gritsenko wrote:
> ... or ThreadLocals are EVIL! If you have not heard the word yet, ThreadLocals 
> tend to prevent (web) application(s) from being garbage collected when thread 
> locals are not properly nulled out.
Yepp, we had to fix such a ThreadLocal in Xalan recently which eat up
3GB of memory in four hours! With the ThreadLocal properly reset, the
app runs at an average of 300MB...

> 
> So in order to allow web applications using LogKit to be properly unloaded, 
> LogKit's ContextMap has to have one more method:
> 
>      /**
>       * Remove current ContextMap.
>       * This method removes a ContextMap associated with current thread,
>       * if there is any.
>       */
>      public static void removeCurrentContext()
>      {
>          c_localContext.set(null);
>      }
> 
> 
> Consistent usage of this method, like:
> 
> try {
>      ... ContextMap.getCurrentContext() ...
> } finally {
>      ContextMap.removeCurrentContext();
> }
> 
> will guarantee that ThreadLocal is properly cleaned up and web app will be 
> properly unloaded. I'd like to include this addition into the release; and IMHO 
> there is no reason to do yet another RC build just because of it :-) because it 
> is simple addition which does not alter any existing behavior.
> 
Hmm, is this really required? The context map has a clear method
clearing all items stored in the map. The only object that is not
removed is the map itself, which shouldn't be a problem.

Carsten

-- 
Carsten Ziegeler - Open Source Group, S&N AG
http://www.s-und-n.de
http://www.osoco.org/weblogs/rael/

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