Java

ViaVersionMylesIsCool/ViaVersion

A Minecraft server plugin that allows newer client versions to connect to older server versions, enabling cross-version compatibility.

db-schedulerkagkarlsson/db-scheduler

A persistent, cluster-friendly task scheduler for Java applications using a single database table.

AssertJ Androidsquare/assertj-android

A deprecated set of AssertJ assertions for testing Android UI components with readable error messages.

mongo-hadoopmongodb/mongo-hadoop

A library enabling MongoDB to serve as input source or output destination for Hadoop MapReduce tasks and ecosystem tools.

LevelDBdain/leveldb

A Java port of LevelDB that aims for feature parity and near-native performance while producing identical data files.

Dripninjudd/drip

A fast JVM launcher that reduces startup times by keeping pre-initialized JVMs in reserve, then discarding them after use.

ReflectASMEsotericSoftware/reflectasm

A high-performance Java reflection library using bytecode generation for faster field, method, and constructor access.

Weak handlerbadoo/android-weak-handler

Memory-safe Android Handler implementation using WeakReferences to prevent memory leaks from delayed messages and runnables.

graphql-spring-bootgraphql-java-kickstart/graphql-spring-boot

A Spring Boot starter for GraphQL servers with built-in support for GraphiQL, Altair, Playground, and Voyager.

MITREid Connectmitreid-connect/OpenID-Connect-Java-Spring-Server

A certified OpenID Connect reference implementation in Java on the Spring platform, serving as an Identity Provider and OAuth 2.0 Authorization Server.

sttpsoftwaremill/sttp

A clean, type-safe HTTP client for Scala supporting synchronous, Future-based, and functional effect system programming styles.

Apache InLong (.4k)apache/inlong

A one-stop, full-scenario integration framework for massive data, supporting data ingestion, synchronization, and subscription.

jsweetcincheo/jsweet

A Java to JavaScript transpiler that leverages TypeScript to write web and mobile applications using Java tooling.

playwright-javamicrosoft/playwright-java

Java library for cross-browser web automation and testing with a single API.

nvim-jdtlsmfussenegger/nvim-jdtls

Extensions for the built-in LSP support in Neovim to integrate the Eclipse JDT Language Server for Java development.

Bubbles for Androidtxusballesteros/bubbles-for-android

An Android library for adding Facebook Messenger-style chat heads (floating bubbles) to your applications.

MessagePackmsgpack/msgpack-java

A fast and compact binary serialization library for Java, implementing the MessagePack format as an efficient alternative to JSON.

Project Nessieprojectnessie/nessie

A transactional catalog for data lakes with Git-like semantics, enabling version control and branching for data assets.

Frodoandroid10/frodo

An Android library for logging RxJava Observables and Subscribers with annotation-based debugging.

mantisNetflix/mantis

A platform for building realtime, cost-effective, operations-focused applications.

FiloDBfilodb/FiloDB

A distributed, Prometheus-compatible, real-time, in-memory time series database designed for massive scalability and low-latency operational metrics.

FF4Jff4j/ff4j

A comprehensive Java library for implementing feature flags with runtime toggling, AOP, monitoring, and multi-database support.

BotaniaVazkii/Botania

A Minecraft tech mod themed around natural magic, focusing on plant-based automation and magical systems.

WrongSecretsOWASP/wrongsecrets

An OWASP training app with 62 challenges demonstrating real-world secrets management mistakes and how to find them.

Anvilanvil-ui/anvil

A minimal reactive UI library for Android inspired by React, enabling declarative views with efficient updates.

Google HTTP Clientgoogleapis/google-http-java-client

A flexible, efficient Java library for accessing web resources via HTTP with pluggable transports and data models.

Reactive Kafkaakka/alpakka-kafka

A Reactive Streams connector for Apache Kafka built on Akka Streams, enabling back-pressured integration for Java and Scala.

Galengalenframework/galen

An open-source layout and functional testing framework for web applications using Selenium and a custom spec language.

Tailorsleekbyte/tailor

A cross-platform static analyzer and linter for Swift that enforces style guidelines and helps avoid bugs.

StackGres Operatorongres/stackgres

A full-stack PostgreSQL distribution for Kubernetes, providing an enterprise-grade Postgres stack with HA, backups, monitoring, and more.

Nightcodeoakes/Nightcode

A simple, lightweight IDE specifically designed for Clojure and ClojureScript development.

NLG-evalMaluuba/nlg-eval

A Python library for evaluating natural language generation models using multiple unsupervised automated metrics.

DataStax Java Driverdatastax/java-driver

A modern, feature-rich Java client library for Apache Cassandra, DataStax Enterprise, and DataStax Astra databases.

Mapsforgemapsforge/mapsforge

A vector map library and writer for rendering OpenStreetMap data on Android and desktop Java applications.

ImageJ2imagej/imagej2

An open-source, N-dimensional image processing platform for scientific imaging with a modular, headless architecture.

react-native-webview-bridgealinz/react-native-webview-bridge

A React Native WebView component with a JavaScript bridge for bidirectional communication between native and web content.