Re: Proposed new Java feature

From:

Daniel Pitts <newsgroup.nospam@virtualinfinity.net>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 27 May 2012 11:46:24 -0700

Message-ID:

<8Euwr.47425$On2.20024@newsfe16.iad>

On 5/27/12 11:00 AM, Mike Schilling wrote:

"markspace"<-@.> wrote in message news:jptkmp$vbg$1@dont-email.me...

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?

That acts on an individual ThreadLocal (and works quite well), but it
doens't allow removing all ThreadLocals that might have been accumlated.

You're basically saying "This type of resource can leak if not cleared
appropriately, so there should be a 'Release all resources' method."

When paraphrased that way, does that make it clearer why it isn't a good
idea? It would be about the same as a "File.closeAll()" or a
"Socket.closeAll()" call. Extremely dangerous and only a crutch for not
doing the right thing to begin with.