After come debugging here is what I see: 1. TCPServer does get request from the 'A' and send back non-empty map (instance of Immutables.ImmutableMapWrapper) for the requested node. 2. TCPDelegatingCacheLoaders does get an empty Immutables.ImmutableMapWrapper even though I see that it actually restores non-empty FastCopyHashMap in the process of reading from the stream. Can this be some kind of de-serialization bug? Thank you. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4198973#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...