[jboss-jira] [JBoss JIRA] Resolved: (JBTM-182) Missing synchronization?

Missing synchronization? ------------------------ Key: JBTM-182 URL: http://jira.jboss.com/jira/browse/JBTM-182 Project: JBoss Transaction Manager Issue Type: Task Security Level: Public(Everyone can see) Components: JTA Implementation Affects Versions: 4.2.3 Reporter: Mark Little Assigned To: Jonathan Halliday Fix For: 4.2.3 In addSynchronization for TwoPhaseCoordinator, the synchronization object is created if it isn't already set: if (_synchs == null) { // Synchronizations should be stored (or at least iterated) in their natural order _synchs = new TreeSet(); } if (_synchs.add(sr)) { result = AddOutcome.AR_ADDED; } However, because multiple threads could be calling the same transaction instance concurrently, shouldn't there be a synchronization around this block? It's possible that two threads could test and try to set the _synchs and because of interleaving one thread creates _synchs after the other thread already has and added it's resource (which would then become garbage).