Preloading Tricks

Overview

Preloading Tricks is a developer-only mod that enables advanced operations during the very early stage of the mod loader. It provides early hooks, Java Instrumentation-based class transformation, and SPI-driven callbacks for loader extension.

Supported environments:

• 1.20.1 – Forge & Fabric
• 1.21.x – NeoForge & Fabric

You can test on more version since it's depends on the loader version instead of Minecraft version

Features

• Early loader entrypoints via PreloadingTricksCallback

  • onSetupLanguageAdapter – early setup stage
  • onSetupMods – modify mod list (add/remove via loader API)

• Instrumentation-powered ClassTransform Can transform already-loaded classes, including Java core and classloader classes.

ClassTransform Configuration

To enable transformations, add the following attribute to your MANIFEST.MF:

ClassTransformConfig: xxxx.classtransform.json

Example config (xxxx.classtransform.json):

{
  "package": "settingdust.preloading_tricks.neoforge.transformer",
  "transformers": [
    "mod_setup_hook.FMLLoaderTransformer"
  ]
}

For developers who need to reach into the earliest moments of Minecraft’s loading process.