Mailing-List: contact derby-dev-help@db.apache.org; run by ezmlm
Precedence: bulk
Reply-To: <derby-dev@db.apache.org>
Message-ID: <6898414.1238163290800.JavaMail.jira@brutus>
Date: Fri, 27 Mar 2009 07:14:50 -0700 (PDT)
From: "Myrna van Lunteren (JIRA)" <jira@apache.org>
To: derby-dev@db.apache.org
Subject: [jira] Commented: (DERBY-4124) Broken double-checked-locking in
 EmbeddedDataSource.findDriver
In-Reply-To: <1708404682.1238139530558.JavaMail.jira@brutus>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/DERBY-4124?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12689905#action_12689905 ] 

Myrna van Lunteren commented on DERBY-4124:
-------------------------------------------

This is an interesting observation...but I want to put in 1 cautionary comment; the stated webpage has no licensing/copyrighting info, but it's not clear to me whether the solution came from one of the mentioned articles or was found by one of the contributing/signing people.
We can't use this fix if there's a copyright on it.

> Broken double-checked-locking in EmbeddedDataSource.findDriver
> --------------------------------------------------------------
>
>                 Key: DERBY-4124
>                 URL: https://issues.apache.org/jira/browse/DERBY-4124
>             Project: Derby
>          Issue Type: Bug
>          Components: JDBC
>    Affects Versions: 10.4.2.0
>         Environment: all
>            Reporter: Ronald Tschalaer
>
> org.apache.derby.jdbc.EmbeddedDataSource.findDriver() uses the
> double-checked-locking idiom for setting the 'driver' variable. This
> idiom is, however, not correct and hence the code is broken. The fix
> is to remove the outer if, i.e. to always enter the synchronized block.
> See also
> http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.