concurrency issue with Factory?

I just stumbled across the new Factory class in org.directwebremoting.extend and noticed a couple of problems. The very minor one is that it seems to have been generified from code that was specific to JsonParser, e.g., get(ServletContext) is documented as returning "The current JsonParser".

The more interesting one is that the builder field (and thus the entire class) is not safe for concurrent access. It might be that instances of Factory are meant to be confined to a single thread, in which case the documentation should reflect that. If not, though, builder should be made a volatile or be guarded by a lock.

--tim