Collectible Card Game Headquarters

After enabling several AI players, a mutiplayer game for several humans would be also very desirable.

So... how to reach that? I am not sure hotseat is a good option - that's not really a game when opponent sees your hand from time to time. That is why we should aim directly for network.

I am at the least extent interested in implementing a custom network protocol, sending raw packets for chat or player actions. That is why I thought of making over-network interaction based on some messaging system, like XMPP. Any kind of command will be serialized to string, and a most simple remote client would be a jabber client.

Imagine a server speaking with its remote players by icq.. ohh.. jabber, so that clients recieve only the information they are allowed know. The most advanced players might play just with their chat client, others might use special clients, special lightweight ones, or the the old good forge application.

That is relativelly far concern, to implement somewhere after 1.3.1

Hmm... good ideas, and I like how you want to be very forge-independent in the communication protocol. But, for a first prototype at least, I'd suggest to go with standard Java serialization; that's nowhere near a custom network protocol (after all, you wouldn't consider a new grammar of XML elements a custom protocol) and probably the easiest to implement for Java-Java communication. Also, this is likely the most common usecase, and with your work on player abstraction, it shouldn't be too hard to implement a more sophisticated protocol later, and even to support multiple protocols at once.