Java

RecafCol-E/Recaf

A modern Java bytecode editor that simplifies reverse engineering and modification of Java and Android applications.

nanohttpdNanoHttpd/nanohttpd

A lightweight, embeddable HTTP server library for Java applications, packaged as a single Java file.

AlluxioAlluxio/alluxio

A distributed caching platform that bridges computation frameworks and storage systems for large-scale analytics and ML workloads.

error-pronegoogle/error-prone

A static analysis tool for Java that catches common programming mistakes at compile-time.

rest-assuredrest-assured/rest-assured

A Java DSL for simplifying testing and validation of REST APIs with a fluent, Groovy-like syntax.

gatlinggatling/gatling

An open-source load testing platform for modern performance engineering with code-first test definition and asynchronous architecture.

ArnoldClhartikk/ArnoldC

A programming language where all keywords are Arnold Schwarzenegger movie one-liners, creating humorous and memorable code.

OpenWhiskapache/openwhisk

An open-source serverless platform for building cloud applications with functions, workflows, and event-driven automation.

jOOQjOOQ/jOOQ

A type-safe internal DSL and code generator for writing SQL in Java with full IDE support.

LeafMeituan-Dianping/Leaf

A high-performance distributed ID generation service offering segment and snowflake algorithms, used internally at Meituan-Dianping.

sourcerer-appsourcerer-io/sourcerer-app

Creates a visual profile for software engineers by analyzing their GitHub and git repositories.

Gephi Datasetsgephi/gephi

An award-winning open-source platform for visualizing and manipulating large graphs and networks.

Gephigephi/gephi

An open-source platform for visualizing and manipulating large graphs and networks with real-time performance.

Hazelcasthazelcast/hazelcast

A unified real-time data platform combining stream processing with a fast data store for instant action on data-in-motion.

GraphHoppergraphhopper/graphhopper

A fast, open-source routing engine for OpenStreetMap, usable as a Java library or standalone web server.

KryoEsotericSoftware/kryo

A fast and efficient binary object graph serialization and cloning framework for Java.

Smilehaifengl/smile

A fast and comprehensive machine learning framework for Java, Scala, and Kotlin with state-of-the-art algorithms and data visualization.

Async Http ClientAsyncHttpClient/async-http-client

A high-performance, asynchronous HTTP and WebSocket client library for Java built on Netty.

jsonschema2pojojoelittlejohn/jsonschema2pojo

Generates Java types from JSON or JSON Schema and annotates them for data-binding with Jackson, Gson, etc.

configlightbend/config

A configuration library for JVM languages using HOCON files, supporting JSON, properties, and environment variable substitution.

Drools (.2k)apache/incubator-kie-drools

A Java rule engine, DMN engine, and complex event processing engine for business logic and expert systems.

graphql-javagraphql-java/graphql-java

A Java implementation of the GraphQL specification for building type-safe GraphQL servers.

Overtoneovertone/overtone

An open-source toolkit for designing synthesizers and collaborative music programming using Clojure and SuperCollider.

Apache Hudiapache/hudi

An open data lakehouse platform for incremental data processing with upserts, deletes, and time-travel queries.

Apache NiFi (k)apache/nifi

An easy-to-use, powerful, and reliable system to process and distribute data across cybersecurity, observability, and AI pipelines.

google-java-formatgoogle/google-java-format

A tool that automatically reformats Java source code to comply with Google Java Style guidelines.

javaparserjavaparser/javaparser

A Java 1-25 parser and abstract syntax tree library with advanced analysis capabilities for source code manipulation.

MaterialEditTextrengwuxian/MaterialEditText

An enhanced Android EditText widget implementing Material Design with floating labels, character counters, and custom styling.

J2ObjCgoogle/j2objc

A command-line tool that translates Java source code to Objective-C for iOS app development, enabling code sharing across platforms.

gdalOSGeo/gdal

An open-source translator library for raster and vector geospatial data formats.

JSqlParserJSQLParser/JSqlParser

A Java SQL parser that translates SQL statements into a traversable hierarchy of Java classes, supporting multiple RDBMS dialects.

Aldaalda-lang/alda

A text-based programming language for composing and playing back music using a simple markup-like syntax.

Markorgsantner/markor

A versatile, offline-first text editor for Android supporting Markdown, todo.txt, and other plaintext formats for notes and task management.

DDD By Examples - Libraryddd-by-examples/library

A comprehensive Domain-Driven Design example project implementing a library system with strategic analysis and tactical patterns.

JanusGraphJanusGraph/janusgraph

An open-source, distributed graph database optimized for storing and querying large graphs with billions of vertices and edges.

Sodium (for Fabric)CaffeineMC/sodium-fabric

A Minecraft client optimization mod that improves frame rates, reduces micro-stutter, and fixes graphical issues.