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https://issues.apache.org/jira/browse/ACCUMULO-853?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Christopher Tubbs updated ACCUMULO-853:
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Fix Version/s: 1.5.0
Assignee: Eric Newton
> Fields and parameters that are used as locks change to be final (where
> possible)
> --------------------------------------------------------------------------------
>
> Key: ACCUMULO-853
> URL: https://issues.apache.org/jira/browse/ACCUMULO-853
> Project: Accumulo
> Issue Type: Improvement
> Reporter: Tim Halloran
> Assignee: Eric Newton
> Priority: Minor
> Labels: patch
> Fix For: 1.5.0
>
> Attachments: accumulo.patch
>
>
> Examining locking in the code using SureLogic JSure I noticed many locks are
> not declared final that could be.
> One reference why this may be "bad" is CERT:
> https://www.securecoding.cert.org/confluence/display/java/LCK01-J.+Do+not+synchronize+on+objects+that+may+be+reused
> That said :-), this has two possible impacts of more immediate concern:
> memory model and maintainability.
> 1) The memory model only guarantees publication of final fields that are not
> safely published -- this is highly desired for fields used as lock objects
> because they may be the mechanism for safe publication. Yes it might work,
> but as my buddy Brian Goetz says, Just because you ran around with holding
> scissors all last week and didn't get hurt, is not a good rational to keep
> doing it.
> 2) The CERT "rule" is about mutation -- the final flag helps to clarify that
> the reference to the object used as a lock is not intended to be changed.
> Avoiding a change that breaks a locking model.
> I also changed some lock objects from new String("foo") to new Object() (see
> patch), could be reverted (but left final) if there is some reason for the
> use of the larger String object. There was none I could see.
> I'm trying to verify a large portion of the lock usage statically and use a
> dynamic tool (SureLogic Flashlight) to check other aspects, but this was a
> simple patch I could provide right away as a small improvement.
> I have a patch, will attach (not a Jira expert yet)
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