RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.

A libre lightweight streaming front-end for Android.

High Performance Inter-Thread Messaging Library

Very spicy additions to the Java programming language.

Modifications to the Minecraft base files to assist in compatibility between mods. New Discord: https://discord.minecraftforge.net/

Catch common Java mistakes as compile-time errors

Reformats Java source code to comply with Google Java Style.

Java 1-24 Parser and Abstract Syntax Tree for Java with advanced analysis functionalities.

Keep your code spotless

The missing bridge between Java and native C++

Google Go language IDE built using the IntelliJ Platform

Java bytecode engineering toolkit

Log analyser / visualiser for Java HotSpot JIT compiler. Inspect inlining decisions, hot methods, bytecode, and assembly. View results in the JavaFX user interface.

Lombok Plugin for IntelliJ IDEA

BinNavi is a binary analysis IDE that allows to inspect, navigate, edit and annotate control flow graphs and call graphs of disassembled code.

FST: fast java serialization drop in-replacement

BuildCraft

A sampling JVM profiler without the safepoint sample bias

A Minecraft plugin API

Libre Minecraft mappings, free to use for everyone. No exceptions.

A Forge mod that implements SpongeAPI

Support alternative markup for Apache Maven POM files

Fabric's mostly-version-independent mod loader.

A fast and small JSON parser and writer for Java

Ghidra C++ Class and Run Time Type Information Analyzer

Minecraft mod development framework used by Forge and FML for the gradle build system

Infinite* height mod for Minecraft

Redstone Engineering

Source code for Forestry (Minecraft mod).

QDox - full extractor of Java class/interface/method definitions (including annotations, parameters, param names)