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Aljoscha Krettek commented on FLINK-6007: ----------------------------------------- Or we could duplicate the set of keys before iterating. This way, removal from the original set will be possible while iterating over the copy. > ConcurrentModificationException in WatermarkCallbackService > ----------------------------------------------------------- > > Key: FLINK-6007 > URL: https://issues.apache.org/jira/browse/FLINK-6007 > Project: Flink > Issue Type: Bug > Components: DataStream API > Affects Versions: 1.3.0 > Reporter: Kostas Kloudas > Assignee: Kostas Kloudas > Fix For: 1.3.0 > > > Currently, if an attempt is made to call > {{InternalWatermarkCallbackService.unregisterKeyFromWatermarkCallback()}} > from within the {{OnWatermarkCallback}}, a > {{ConcurrentModificationException}} is thrown. The reason is that the > {{invokeOnWatermarkCallback}} iterates over the list of keys and calls the > callback for each one of them. > To fix this, the deleted keys are put into a separate list, and the deletion > happens after the iteration over all keys has finished. -- This message was sent by Atlassian JIRA (v6.3.15#6346)