It's not immediately obvious whether SieveFactory is thread-safe. From looking at the code, it looks like I can access a single instance of SieveFactory concurrently. Can someone please confirm? It would be nice to have this specified in the javadocs.
One thing I noticed is that CommandManagerImpl, ComparatorManagerImpl, and TestManagerImpl all have a classNameMap instance variable. Seems like everything is safe, as long as I don't try to modify the maps after the server has started. Wouldn't be a bad idea to use ConcurrentHashMap in ConfigurationManager instead of HashMap to handle this edge case.