My friends and I love to play Minecraft occasionally, but it often happens to be in the middle of nowhere, with no internet. The setup is usually more interesting than the actual playing.
We usually begin by sharing the most recent Minecraft binaries and then creating an ad-hoc WiFi connection. Then, we're ready to go!
Minecraft typically performs DRM and verification with the Minecraft website. Tiara This can be removed from the server by setting online-mode false in server.properties. However the client will not allow this to be done.
At first the method was sending someone with a smartphone out to find an open WiFi network. It was possible to fake the login server prior to the launcher. Recently, however, I discovered an option to play offline on the client.
Spoiler alert: Minecraft is The Matrix.
That's it. It had to be said. Now, let's hack Minecraft Matrix style.
You'll be kicked by each other when you click "Play Offline" after an unsuccessful login.
Now, fire up your terminal and change the directory to your bin folder within your Minecraft directory
Although I cannot read and write Matrix as Mouse4 can, the GNU toolchain can. We'll substitute some instances of "Player" by any string of equal length.
The first step is to extract the Jar. It turns out that it works just fine as a directory, and it's much more user-friendly that way.
Now we must decide which files should be modified. Beware of Deja vu!
Some experimentation shows that MinecraftApplet.class is the one that matters. Now you need to use sed to replace "Player" with a different name of equal length5.
Mac users will need to install GNU sed, since BSD sed can muddle the binary file beyond repair. I used brew install gnu sed, but Macports and Fink might also work.