[CONFIGURATION-347] Iterating over the keys of a file-based configuration can cause a ConcurrentModificationException

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.5
• Fix Version/s: 1.6
• Component/s: File reloading
• Assignee: Unassigned
• Reporter: Oliver Heger
• Created: 05/Nov/08 21:06
• Updated: 22/Aug/09 19:36
• Resolved: 06/Nov/08 07:29

Description

Some implementations of FileConfiguration return an iterator in their getKeys() method that is directly connected to the underlying data store. When now a reload is performed (which can happen at any time) the data store is modified, and the iterator becomes invalid.

This behavior is very confusing because ConcurrentModificationExceptions are typically related to multi-threading access. But even if the code performing the iteration is the only instance that accesses the configuration, the exception can be thrown.