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https://issues.apache.org/jira/browse/UIMA-6129?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16937949#comment-16937949
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Marshall Schor commented on UIMA-6129:
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Hi, my understanding of your example: You have a main thread (let's call it
T1), and make another thread T2 for the future task, and launch it. It
references the jcase.
The T1's get(... with timeout) times out, then proceeds to access that same
JCas while the T2 is still running and making annotations. This may cause the
concurrent modification exception: T1 is iterating over Annotations, while,
simultaneously, T2 could be adding to the the Annotation index. causes lots of
problems, including the two you saw (possible thread interlock and concurrent
modification exception).
This might also be causing the thread deadlock, when T2 modifies the JCas
indexes at the same time T1 is reading them.
A way around this could be to surround all the code in both T1 and T2 that do
access to the same JCas with a synchronization lock, to prevent both from
running at the same time.
> The thread may deadlock if other thread interrupted which use jcas
> -------------------------------------------------------------------
>
> Key: UIMA-6129
> URL: https://issues.apache.org/jira/browse/UIMA-6129
> Project: UIMA
> Issue Type: Bug
> Components: UIMA
> Affects Versions: 2.10.4SDK
> Reporter: li Gongrong
> Priority: Major
>
> I use FutureTask to kill the thread spend a lot of time，but it will cause
> deadlock.
> {code:java}
> at sun.misc.Unsafe.park(Native Method)at sun.misc.Unsafe.park(Native Method)
> - parking to wait for <0x000000070435e808> (a
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) at
> java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
> at
> org.apache.uima.jcas.impl.JCasHashMapSubMap.getReserve(JCasHashMapSubMap.java:303)
> at org.apache.uima.jcas.impl.JCasHashMap.getReserve(JCasHashMap.java:318) at
> org.apache.uima.jcas.impl.JCasImpl.getJfsFromCaddr(JCasImpl.java:1154) at
> org.apache.uima.jcas.impl.JCasImpl$JCasFsGenerator.createFS(JCasImpl.java:912)
> at
> org.apache.uima.jcas.impl.JCasImpl$JCasFsGenerator.createFS(JCasImpl.java:873)
> at org.apache.uima.cas.impl.CASImpl.ll_getFSForRef(CASImpl.java:3751) at
> org.apache.uima.cas.impl.CASImpl.createFS(CASImpl.java:2231) at
> org.apache.uima.cas.impl.FSIteratorWrapper.get(FSIteratorWrapper.java:63) at
> org.apache.uima.cas.impl.FSIteratorAggregate.get(FSIteratorAggregate.java:76)
> at
> org.apache.uima.cas.impl.FSIteratorImplBase.next(FSIteratorImplBase.java:66)
> at
> org.apache.uima.cas.impl.FSIteratorImplBase.next(FSIteratorImplBase.java:32)
> {code}
> why ?
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