[jira] [Created] (CMIS-769) CacheImpl is not thread safe (org.apache.chemistry.opencmis.client.bindings.cache.impl.CacheImpl)

["Trask Stalnaker (JIRA)" <ji...@apache.org>]

Trask Stalnaker created CMIS-769:
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             Summary: CacheImpl is not thread safe (org.apache.chemistry.opencmis.client.bindings.cache.impl.CacheImpl)
                 Key: CMIS-769
                 URL: https://issues.apache.org/jira/browse/CMIS-769
             Project: Chemistry
          Issue Type: Bug
          Components: opencmis-client
    Affects Versions: OpenCMIS 0.10.0
            Reporter: Trask Stalnaker


We ended up with a thread stuck in an infinite loop at:

java.lang.Thread.State: RUNNABLE
java.util.LinkedHashMap.transfer(Unknown Source)
java.util.HashMap.resize(Unknown Source)
java.util.LinkedHashMap.addEntry(Unknown Source)
java.util.HashMap.put(Unknown Source)
org.apache.chemistry.opencmis.client.bindings.cache.impl.AbstractMapCacheLevel.put(AbstractMapCacheLevel.java:56)
org.apache.chemistry.opencmis.client.bindings.cache.impl.CacheImpl.put(CacheImpl.java:191)
org.apache.chemistry.opencmis.client.bindings.spi.atompub.LinkCache.addLink(LinkCache.java:133)

The issue seems to be that CacheImpl is using an access-ordered LinkedHashMap via LruCacheLevelImpl, and CacheImpl is using a ReentrantReadWriteLock to synchronize access to the LinkedHashMap, allowing multiple concurrent readers, which is ok for HashMap, but is not ok for an access-ordered LinkedHashMap, see the bolded sentence at http://docs.oracle.com/javase/7/docs/api/java/util/LinkedHashMap.html:

"In access-ordered linked hash maps, merely querying the map with get is a structural modification."




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