Note, I'm not talking about Gaia, but this could be put towards Gaia I guess.

How would one create a custom client that just logs everything received from a gameserver, masquerading as a real game client? The game in question is written in Java.

I've been looking into this for a while with no avail. If anyone could help, that would be great. And I don't just mean capturing packets or whatever, I mean like all of the data that the server sends the client, because from there reverse engineering the client would be MUCH simpler than trying to locate and de-obfuscate code.