
RainAPI
Core library for RainJava featuring embedded ECJ compiler, Javassist bytecode tools, and ASM transformation pipeline. Enables dynamic Java compilation and class modification at runtime.
About this Mod
RainJava API
Advanced Runtime Class Transformation Framework
A foundational library providing Mixin and Coremod interoperability layers, powered by enterprise-grade bytecode and compilation tools.
Overview
RainJava API establishes the critical infrastructure for runtime class transformation pipelines. It serves as a middleware bridge between dynamic compilation workflows and Minecraft's standard modification systems (Mixin & Coremod), ensuring bytecode-level compatibility without compromising game stability.
While designed as the prerequisite foundation for the upcoming RainJava ecosystem, this API functions independently as a robust toolkit for developers requiring deep class manipulation capabilities.
Embedded Libraries
This mod ships with zero-external-dependency versions of industry-standard tools:
Javassist — High-level bytecode manipulation library for runtime class engineering
ECJ (Eclipse Compiler for Java) — Full-featured Java compiler capable of runtime source-to-bytecode transformation
JavaParser — Abstract Syntax Tree (AST) analysis and code generation framework
These libraries are shaded and isolated to prevent conflicts with other mods.
Technical Scope
Transformation Bridge — Facilitates communication between runtime-generated class definitions and established bytecode modification frameworks
Mixin Compatibility Layer — Enables standardized injection patterns to recognize and process dynamically provisioned classes
Coremod Integration — Provides stable hooks for runtime class definitions to participate in Forge's transformation chain
Sandboxed Execution — Implements security boundaries for runtime code evaluation environments
For Modders
Install this API if you:
Plan to develop for or use the upcoming RainJava framework
Require embedded Javassist/ECJ/JavaParser without bundling them yourself
Need stable Mixin/Coremod interoperability for advanced bytecode operations
Available Versions
How to Install RainAPI on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set forge Loader
In the panel under "Egg", select the forge loader and matching Minecraft version (1.20.1).
Install Mod
Open the mod browser in the dashboard and search for "RainAPI". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.20.1
Server-side
✓ RequiredRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
RainAPI server crashes on startup – what to do?
Most common cause: wrong forge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.20.1). You can switch loaders with one click in the panel.
Is RainAPI compatible with forge?
RainAPI officially supports forge for Minecraft 1.20.1. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with RainAPI – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if RainAPI consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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Rent Modded Server
Install RainAPI with just one click on your server.