I see that the new launcher has an offline mode, but I can't figure out how to (1) use offline mode when an internet connection is available, and (2) set user name while in offline mode.
I log in online to play on public smp servers, but I have a private 1.5.2 server running on my home computer in offline mode so I can play several 'personas' on the server. (I have a 'farmer', a 'miner', and an 'adventurer', each going about their lives in the same world). I have been logging into each using batch files to set the user name.
Is there a way to make this setup be compatible with the new update? I have a lot of time and effort put into this world, but can't really justify buying two more accounts to continue this style of playing.
The ideal case would be a way to let the client verify authenticity, but be able to set a username if offline (either from launcher or command line).
First of all, you would not be able to pick a username when playing offline, because you can only use a username online, and playing online means that you bought the game so that would mean you would actually have to buy 2 more accounts if you want different usernames of each player. Second of all, you are asking if you can play offline with an internet connection. Yes you will always be able to play offline whether you have a connection or not.
Thanks for trying to help. I may have been unclear in what I meant. I wasn't referring to single-player mode. I have already been successfully playing "online" (i.e., logged in and authenticated) on smp servers on the internet, but playing "offline" in smp with my own server on a lan for many months, since 1.2.5. It just required starting the minecraft jar directly from command line, as discussed in many other threads here.
The new launcher, at least as of the 1.6 pre-release today, does not give the option to "Play Offline" if it can authenticate the account over the internet. (At least I can't find it.) The Play Offline button goes away if it is able to log in.
I was asking for advice on, first, playing "offline" even though the internet and authentication system are reachable, and, second, entering a player name while in offline mode so I could access multiple characters in my world.
It seems that my launcher is automatically logging in when it loads. I don't know what setting could cause that. If I exit and reload, again the "Play Offline" button is quickly replaced by "Play". I don't know what is different between our setups.
In any case, I found an answer tinkering with the command line launching. So, it looks like I can continue the same approach I had been using in the past... use the launcher and log in for smp servers or single player worlds, and use a command line start to get specific 'characters' in my personal smp server.