What is Lillero?

Lillero is a lightweight and simple Java ASM patching framework built on top of ObjectWeb's ASM library. It can be used in conjunction with any loader that supports the ASM library's ClassVisitor system.

Lillero is made up of multiple components:

• Lillero, the core library.
• Lillero-processor, the annotation processor.
• Lillero-mapper, a library which provides the ability to read multiple obfuscation mapping formats.
• Lillero-mapping-writer, a CLI tool for converting and inverting mapping formats.

On top of these, there's Lillero-loader, a sample loader, in form of a plugin for Minecraft Forge's ModLauncher. Lillero-loader is the only Minecraft-specific part of the Lillero system. To reiterate: while Lillero was initially developed for use with Minecraft, it really works with anything, as long as you have a loader that supports the ASM library.

This book will introduce you to ASM patching and provide an in-depth guide on how to use Lillero to do it in a way that is flexible and yet comfortable.