FAQ - MCPHackers/RetroMCP-Java GitHub Wiki

Q: There's a popup saying "Java Development Kit not found!" when I try to run jar. How do I fix it? A: Make sure that the default java on your PC is a JDK, not a JRE. Alternatively, you can execute the RetroMCP-Java JAR from the terminal with a specific Java install: java -jar RetroMCP-Java-all.jar.

Q: I need to decompile <insert any mod>. How can I do that? A: Run setup for vanilla version that the mod is for. Replace minecraft.jar in jars folder with the one that has the mod installed. Decompile.

Q: How to use Risugami's ModLoader/Forge? A: Same as the above QA, install ModLoader into minecraft.jar before installing Forge. Enable "Strip generics" in RetroMCP-Java to remove decompilation errors. Decompile.

Q: I'm getting errors after decompiling a mod. What should I do? A: Fix all compilation errors in source and run Update MD5 task when you are done.

Q: What is unsupported class file major version XX when running my mod? A: Unsupported class file major version means that you compiled a file with a newer version than what your Java version install supports, or what ASM supports when re-defining classes (such is the case with LaunchWrapper).