[OPENJPA-1467] java.lang.IllegalMonitorStateException in ConcurrentDataCache.writeUnlock()

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-M1, 2.0.0-M2, 2.0.0-M3
• Fix Version/s: 2.0.0-beta
• Component/s: datacache
• Assignee: Richard G. Curtis
• Reporter: Richard G. Curtis
• Created: 18/Jan/10 19:26
• Updated: 24/Feb/10 14:38
• Resolved: 18/Jan/10 19:34

Description

I encountered the following exception when doing some load testing:
Caused by: java.lang.IllegalMonitorStateException
at java.util.concurrent.locks.ReentrantLock$Sync.tryRelease(ReentrantLock.java:139)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.release(AbstractQueuedSynchronizer.java:1187)
at java.util.concurrent.locks.ReentrantLock.unlock(ReentrantLock.java:443)
at org.apache.openjpa.util.CacheMap.writeUnlock(CacheMap.java:203)
at org.apache.openjpa.datacache.ConcurrentDataCache.writeUnlock(ConcurrentDataCache.java:108)
at org.apache.openjpa.datacache.DataCacheStoreManager.cacheStateManager(DataCacheStoreManager.java:382)
at org.apache.openjpa.datacache.DataCacheStoreManager.initialize(DataCacheStoreManager.java:353)
at org.apache.openjpa.kernel.DelegatingStoreManager.initialize(DelegatingStoreManager.java:111)
at org.apache.openjpa.kernel.ROPStoreManager.initialize(ROPStoreManager.java:57)
at org.apache.openjpa.kernel.BrokerImpl.initialize(BrokerImpl.java:998)
at org.apache.openjpa.kernel.BrokerImpl.find(BrokerImpl.java:956)
... 43 more

At first glance it seemed impossible that this exception was happening... Everywhere that CacheMap.writeUnlock() is called there is a corresponding CacheMap.writeLock() prior to that call.

I discovered that the bug is in org.apache.openjpa.datacache.ConcurrentDataCache.removeAllInternal(Class<?> cls, boolean subs). The problem is that this method modifies the underlying cache, but doesn't obtain a writeLock first.