Hi, > but I'm not convinced that guaranteeing more than JSR-170 > says would be good for interoperability of clients.
Maybe trying to detect concurrent access and throwing an exception would be an option? From HashMap javadocs: "Fail-fast iterators throw ConcurrentModificationException on a best-effort basis... the fail-fast behavior of iterators should be used only to detect bugs..." That way we don't have to synchronize, but also reduce the risk of corrupted internal structures on concurrent access within the same session. Thomas
