Re: A question about synchronized threads

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 04 May 2011 12:45:51 -0400
Message-ID:
<iprvpo$c9g$2@news.albasani.net>
On 05/03/2011 08:17 PM, Deeyana wrote:

On Tue, 03 May 2011 18:57:19 -0400, Lew wrote:

byhesed wrote:

I thought that synchronizing entire methods would be wasteful.


Why?


It is well known that shorter critical sections and finer lock
granularity can increase concurrency, Lew.

Also, if two methods are "totally unrelated to each other" then you
don't need any synchronization at all.


Classic unsubstantiated and erroneous claim. They may still need
synchronization to prevent the simultaneous use of a) the SAME one by two
different threads on the same object or b) one of them and some third
method on the same object. But you may want an explicit lock object
instead of the default effects of declaring the methods synchronized.

The single best, most effective way to optimize concurrent code is not
to share data. The second-best way is to make shared-data immutable
(read-only).


Clojure can help a lot with the latter.


Plonk, schmuck.

--
Lew
Honi soit qui mal y pense.
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