[concurrency-interest] Double Checked Locking in OpenJDK

Vitaly Davidovich vitalyd at gmail.com
Tue Aug 14 19:19:06 EDT 2012


This is a general problem - can have a tangled mess of single threaded code.

Luckily, the jvm is a nice platform with good tooling for dealing with
threading issues, certainly better than a lot of others.

Sent from my phone
On Aug 14, 2012 7:13 PM, "√iktor Ҡlang" <viktor.klang at gmail.com> wrote:

>
>
> On Wed, Aug 15, 2012 at 12:59 AM, Nathan Reynolds <
> nathan.reynolds at oracle.com> wrote:
>
>>  I would hope the average programmer would simply need to know they
>> should use synchronized blocks when accessing shared state.  If the lock
>> becomes contended, then the experts will have to step in and figure out how
>> to get rid of the lock and deal with all of these issues.
>>
>
> Unfortunately the sad fact is that when you as an "expert" come into a
> codebase loitered with synchronized statements, it's completely
> demoralizing trying to untangle it since most people do not know when or
> why to use them.
>
> Cheers,
>>
>
>>
>>
>>  Nathan Reynolds<http://psr.us.oracle.com/wiki/index.php/User:Nathan_Reynolds>| Consulting Member of Technical Staff |
>> 602.333.9091
>> Oracle PSR Engineering <http://psr.us.oracle.com/> | Server Technology
>>  On 8/14/2012 3:49 PM, Raoul Duke wrote:
>>
>> On Tue, Aug 14, 2012 at 3:36 PM, Vitaly Davidovich <vitalyd at gmail.com> <vitalyd at gmail.com> wrote:
>>
>>  I think the lesson should be avoid data races - period. :) if you find a
>> case where you can justify it (i.e. profiling/testing guided) then consider
>> it.  I bet there will be few and far in between cases like that.
>>
>>  sincere, if vulgar, question: as a run-of-the-mill Joe Average
>> programmer, how the heck do i even know that i've managed to avoid
>> them? and if i do manage to avoid them, have i not just basically
>> walked into potential, hiding, secret, waiting until after i ship to
>> show up, deadlockville? (all in all, shared-mutable-state-concurrency
>> seems pretty bad.)
>>
>> sincerely.
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>
>
> --
> Viktor Klang
>
> Akka Tech Lead
> Typesafe <http://www.typesafe.com/> - The software stack for applications
> that scale
>
> Twitter: @viktorklang
>
>
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