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From: markspace <-@.>
Newsgroups: comp.lang.java.programmer
Subject: Re: Proposed new Java feature
Date: Sun, 27 May 2012 09:28:08 -0700
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On 5/26/2012 4:11 PM, Mike Schilling wrote:

> Proposed feature: a static method on Thread that clears all ThreadLocals for
> the current thread.
>


I can see your points.  However, I don't have any real experience with 
ThreadLocal, and when a neophyte agrees with your argument, that's a red 
flag.

Here's a blog where someone seems to have the same issue as you.

<http://weblogs.java.net/blog/jjviana/archive/2010/06/10/threadlocal-thread-pool-bad-idea-or-dealing-apparent-glassfish-memor>

At the end of the comments, there's a suggestion to use 
ThreadLocal::remove(), with the implication that it allows the thread 
local variable to be garbage collection.  Is there a reason that doesn't 
work for you?

My other thought is that "for the current thread" could be improved with 
"for a given thread."  So, inside an Executor, I can just call

   Thread t = ...
   // .. use the thread ..
   Thread.removeLocals( t );
   // now add the thread back into the pool...

And this seems better because I don't have to rely on the users of a 
thread remembering to do it themselves.  External control seems better here.