Exception in thread "GeneralSTPool-14" java.lang.NullPointer

[xone]

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L2J Revision Number:Changeset 4443
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Anyone know what this is ?

Exception in thread "GeneralSTPool-14" java.lang.NullPointerException
at javolution.util.FastList$Node.access$000(FastList.java:768)
at javolution.util.FastList$FastListIterator.next(FastList.java:1020)
at com.l2jserver.gameserver.instancemanager.ItemsOnGroundManager$StoreIn
Db.run(ItemsOnGroundManager.java:228)
at com.l2jserver.gameserver.ThreadPoolManager$RunnableWrapper.run(Thread
PoolManager.java:86)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(Unknown Source)

at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
access$101(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
runPeriodic(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source
)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Another one:

Exception in thread "GeneralSTPool-13" java.lang.NullPointerException
at javolution.util.FastList$Node.access$000(FastList.java:768)
at javolution.util.FastList$FastListIterator.next(FastList.java:1020)
at com.l2jserver.gameserver.instancemanager.ItemsOnGroundManager$StoreIn
Db.run(ItemsOnGroundManager.java:228)
at com.l2jserver.gameserver.ThreadPoolManager$RunnableWrapper.run(Thread
PoolManager.java:86)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRunAndReset(Unknown Source)

at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
access$101(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
runPeriodic(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source
)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

[benurb]

Concurrency issue ^^ Replace the collection that is iterated over (in the lines you see in stack trace) with a thread safe collection (FastList/FastMap.shared(), CopyOnWriteArrayList, ConcurrentHashMap, etc.), do neccessary synchronization, and post a diff in "User Contributions" forum ^^