Map serialization problem

Question

Greetings, gurus.
I have a weird problem I cannot overcome quite a long time now.
I have a client-server application I am developing. Server holds a handler, which accepts requests and sends responses.
In one scenario, the request is received, response object is created (some custom class I have written), and an attachment is added to response.
Now, on application loading, the Response is sent with Map (HashMap actually) attached, everything is good by now.
On some client interaction, I send the same response once again (of course a new object), and I attach new updated Map to it.
The problem is that attachment received on client side is the old map, and not the new one.
I have debugged the whole process several times, and it is as weird as it can get.
The Map on the exit is OK, it is up-to-date, but when I receive it on the client side - it is the old one.
Looks like it is some cache issue.
Has anyone encountered such problems before?
Any advice will be helpful.

Answer 1

However, the way I would do it is use an api like mine [Essence RMI|http://www.freshvanilla.org:8080/display/essence/Essence+Remote+Method+Invocation] so that you don't need to keep resending the Map but instead have a proxy to the map.
eg. In this unit test I create a proxy from the client to the server and then access it as if it were local. RmiMapTest
The latency can be 20-120 microseconds depending on your configuration and is much faster than Java Serialization/Java RMI.
Note: the client can update the Map as well are get the latest values.
I have another example for sharing a BlockingQueue for distributing work to multiple clients.