NilLoader Installer

A small cross-platform installer for NilLoader.

This is an unofficial build It is not affiliated with or endorsed by the original NilLoader project.

The goal is to turn the current manual Java-agent setup into a normal launcher-oriented install flow.

Supported launchers

• Minecraft Launcher (official / Mojang, including the Microsoft Store profile database): detects existing installations, clones the selected installation, downloads NilLoader as NilLoader.jar, and adds the upstream-compatible -javaagent:NilLoader.jar argument only to the cloned profile.
• Prism Launcher
• PolyMC
• MultiMC-compatible instances: writes the NilLoader component patch directly into the instance patches/ directory.

Safety behavior

• The official launcher profile database is backed up before editing.
• Existing non-NilLoader official installations are not modified; a separate + NilLoader installation is created. Existing NilLoader profiles can be repaired in place.
• Existing Prism/PolyMC NilLoader patches are backed up before replacement.
• Downloaded NilLoader agents are validated as JARs and checked for a valid Premain-Class before launcher configuration is changed.
• Nilmods can be placed in the generated nilmods/ directory.

Requirements

• Java 17 or newer to run the installer.
• Close the Minecraft/Prism/PolyMC launcher before installing so it does not overwrite configuration files while they are being changed.

Build

With Gradle:

gradle clean jar
java -jar build/libs/NilLoaderInstaller-0.1.2+unofficial.jar

No third-party runtime dependencies are used.

You can also build without Gradle:

Linux/macOS:

./build.sh

Windows:

build.bat

The standalone jar is written to dist/NilLoaderInstaller-0.1.1+unofficial.jar.

NilLoader version

The installer currently targets NilLoader 1.3.6, matching the current official Prism component metadata documented by NilLoader.

Project layout

• LauncherDetector — discovers official and MultiMC-family installations/instances.
• OfficialLauncherInstaller — clones or repairs an official launcher profile and injects the canonical relative Java agent argument.
• PrismInstaller — installs the NilLoader component patch.
• Downloader — downloads the NilLoader agent for the official launcher flow.
• Json — tiny dependency-free JSON reader/writer used for launcher configuration.

License

MIT. NilLoader itself is a separate project and remains under its own license.