Minecraft Jar Tool
Simplify the process of modifying the Minecraft game files to install custom modifications. Open the minecraft.jar file and manage the integration of additional information, parameter changes, etc. Save the results and quickly access them in the game itself.
You can download Minecraft Jar Tool 1.0 for Mac from our software library for free. This free software is suitable for Mac OS X 10.5 or later. This Mac download was scanned by our antivirus and was rated as virus free. The program lies within Games, more precisely Tools. The unique identifier for this app's bundle is com.ipodtouchdude.Minecraft-Jar-Tool. This free Mac app was originally developed by ipodtouchdude. The most popular version among the application users is 1.0.
From the developer:
Minecraft Jar Tool its a freeware tool for the most good knowed game Minecraft for patching and backup.
If you do mess up you Minecraft.jar file delete the files from ~/Library/Application Support/minecraft/bin/ and open the Minecraft.app up and they should redownload. And you should not lose your Minecraft saves
You may want to check out more software for Mac, such as Tools for Television PRO, Make My App - Mockup Tools for Developers or Smart Screen Tool - Capture Video, which might be related to Minecraft Jar Tool.