[jboss-dev] Strange java.util.LinkedList.contains() NPE

[Scott M Stark]

We should change that to a CopyOnWriteArrayList<E> since were jdk5 based
in 4.2.

Dimitris Andreadis wrote:
> Andrew Dinn wrote:
>> Andrew Dinn wrote:
>>> Andrew Dinn wrote:
>>>> It could be a concurrency bug. The relevant code is
>>>>
>>>> . . .
>>>> 105            for (Entry e = header.next; e != header; e = e.next) {
>>>> 106                if (o.equals(e.element))
>>>> 107                    return index;
>>>> 108                index++;
>>>> 109            }
>>>> . . .
>>>
>>> Oops, first off, apologies for posting an analysis which was
>>> obviously wrong.
>>
>> Ok, I know I'm replying to my own reply to my reply but I'll just note
>> that my initial analysis was not 'obviously' wrong. It's actually more
>> subtle than that as it might just be right depending upon whether the
>> value of field header is refetched if a yield occurs between execution
>> of 'e = header.next' and 'e != header'. This may or may not happen at
>> a compiler's whim since the code does not employ any synchronization.
>>
>> Anyway, a concurrent remove is a much more likely culprit.
> 
> Yes, seems like a concurrent access issue. On the other hand, concurrent
> access to the MainDeployer is not really common in the testsuite. There
> is just the scanner thread and the testsuite that may perform
> deployments/undeployments.
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