[Helma-user] java.util.ConcurrentModificationException on app.addRepository

[Kris Leite]

On Sun's web site they had a note for 
java.util.ConcurrentModificationException:
~~~~~~~~~~~

Note that this exception does not always indicate that an object has 
been concurrently modified by a /different/ thread. If a single thread 
issues a sequence of method invocations that violates the contract of an 
object, the object may throw this exception. For example, if a thread 
modifies a collection directly while it is iterating over the collection 
with a fail-fast iterator, the iterator will throw this exception.
~~~~~~~~~~~

The error is pointing to an Interator in a loop.  Looking at the looping 
and what is being loaded might be of interest.

my 2cents,
Kris Leite

Axel Zuzek wrote:
>
>
> 2008/7/17 Axel Zuzek <axel.zuzek at knallgrau.at 
> <mailto:axel.zuzek at knallgrau.at>>:
>
>     hi hannes,
>
>     your patch changed something, but didn't solve the problem (the
>     error occours now (reproduceable) at a later repository dir, see
>     logmessages below
>
>
> update: it seems to be a race condition, because the occurrence of the 
> error varies now between delicious and places widget
>
>
>     ...
>     [2008/07/17 14:36:13] [INFO] START INFO load widgets [Application
>     twoday_w1_s2]
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\0_rss\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\amazon\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\archive\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\credits\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\delicious\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\feeds\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\flickr\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\linkList\code
>     [2008/07/17 14:36:13] [ERROR] null:
>     java.util.ConcurrentModificationException
>
>     java.util.ConcurrentModificationException
>             at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
>             at java.util.HashMap$ValueIterator.next(HashMap.java:821)
>             at
>     java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1010)
>             at
>     helma.scripting.rhino.RhinoCore.updatePrototypes(RhinoCore.java:348)
>
>             at
>     helma.scripting.rhino.RhinoEngine.enterContext(RhinoEngine.java:174)
>             at
>     helma.framework.core.RequestEvaluator.run(RequestEvaluator.java:172)
>             at java.lang.Thread.run(Thread.java:619)
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\meebo\code
>     [2008/07/17 14:36:13] [INFO] ---- adding repository
>     C:\helma-1.6.2\apps\twoday_w1_1_1\core\widgets\plazes\code
>     ...
>
>     2008/7/17 Hannes Wallnoefer <hannes at helma.at
>     <mailto:hannes at helma.at>>:
>
>
> ------------------------------------------------------------------------
>
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