For the last few days, I've been trying out the Better than Wolves mod for Minecraft.  The mod makes a lot of things harder, and most importantly, adds mechanical power to the game alongside the magical redstone power it already had.  With tools like MCPatcher, this sort of thing is pretty easy, but once again minecraft's Java bit us in the butt when it turned out Sarah's computer, which runs the Mac OS version 10.5 is no longer supported and doesn't have a version of Java later than 6.

Apparently, it comes configured to use version 5, though.  For some reason.

Anyway, we spent the last day trying different ways of patching the game so she could use it, including doing it on a GNU/Linux box and emailing the modified jar file to her.  The most coherent thing I could recognize out of the Java backtrace was something about class versions.  I know Java is stored in class files, and so I reasoned it was something about some version of Java not playing well.

Long story short, if you find yourself in the same position, follow the instructions of the fellow here, which I will reproduce below in case the forum they are posted to has ceased to exist.

  1. Right click the Minecraft App and select "Show Package Contents", then select info.plist

  2. In info.plist look for the lines of "JVMVersion 1.5+" change the 5 to a 6 then save and close the file

  3. Open a finder window and go to /System/Library/Frameworks/JavaVM.framework /Resources/Mac OS

  4. Copy the file named JavaApplicationStub

    1. Go back to the Contents folder in the Minecraft app

    2. Open the folder MacOS

    3. Paste JavaApplicationStub into the folder

  5. Next find and open “Java Preferences” in finder

  6. In the “General” tab there should be a list of the Java versions you have. If “Java SE 6″ isn’t on the top of the list then drag it to the top.

  7. Patch Minecraft at will

That is all.