Java

KolobokeOpenHFT/Koloboke

A Java Collections Framework extension with high-performance primitive specializations and drop-in replacements for JDK collections.

bifurcanlacuna/bifurcan

A Java library providing high-performance mutable and immutable data structures with functional semantics, efficient batch operations, and custom equality.

MySQL Connector/Jmysql/mysql-connector-j

Official JDBC driver for MySQL, implementing JDBC 4.2 and MySQL X DevAPI for Java applications.

zerocodeauthorjapps/zerocode

A no-code automated testing framework for microservices APIs, Kafka data streams, databases, and load testing using JSON/YAML.

android-BluetoothChatgooglesamples/android-BluetoothChat

Android sample demonstrating Bluetooth Classic communication between devices using RFCOMM sockets.

JsonUnitlukas-krecan/JsonUnit

A Java library for comparing JSON documents in unit tests with flexible assertions and integration with popular testing frameworks.

ActiveJactivej/activej

A modern Java platform providing high-performance asynchronous I/O, HTTP server/client, dependency injection, and cloud components with minimal dependencies.

WSO2 API Managementwso2/product-apim

A complete platform for building, integrating, and exposing digital services as managed APIs in cloud, on-premise, and hybrid architectures.

blazegraphblazegraph/database

An ultra high-performance graph database supporting Blueprints and RDF/SPARQL APIs, scaling to 50 billion edges on a single machine.

Fijifiji/fiji

A batteries-included distribution of ImageJ for scientific image processing, focused on life sciences research.

Android Basic Samplesplaygameservices/android-basic-samples

Android sample apps demonstrating Google Play game services integration including leaderboards, achievements, and snapshots.

Stripestripe/stripe-java

The official Java client library for integrating with the Stripe API to process payments and manage billing.

storm-crawlerDigitalPebble/storm-crawler

A scalable, mature, and versatile web crawler built on Apache Storm for building low-latency, distributed crawling systems.

AWS CloudWatch exporterprometheus/cloudwatch_exporter

A Prometheus exporter that fetches metrics from Amazon CloudWatch and exposes them for monitoring.

Defects4Jrjust/defects4j

A database of reproducible real-world Java bugs and a framework for controlled software engineering experiments.

Nakadizalando/nakadi

A distributed event bus broker providing a RESTful API abstraction over Kafka-like queues for real-time data streaming.

Spatial4jlocationtech/spatial4j

A general-purpose geospatial Java library providing shapes, distance calculations, and format support for Euclidean and geodesic models.

Livyapache/incubator-livy

A REST interface for interacting with Apache Spark from anywhere, enabling remote code execution and job submissions.

DataSketchesDataSketches/sketches-core

A Java library of stochastic streaming algorithms (sketches) for approximate analysis of massive datasets.

Zally ()zalando/zally

A minimalistic, simple-to-use linter for OpenAPI 2 and 3 specifications that checks compliance with RESTful guidelines.

CoreProtectPlayPro/CoreProtect

A fast data logging and anti-griefing plugin for Minecraft servers.

RestExpressRestExpress/RestExpress

A minimalist Java framework for rapidly creating scalable, containerless RESTful microservices using Netty.

uniVocity-parsersuniVocity/univocity-parsers

A suite of extremely fast and reliable parsers for Java with a consistent interface for multiple file formats.

ownerlviggiano/owner

A Java API that eliminates boilerplate code for handling configuration properties files.

Ashleylibgdx/ashley

A tiny, high-performance Java entity framework for game development, inspired by Ash and Artemis.

Record-BuilderRandgalt/record-builder

An annotation processor that generates builders, withers, and records for Java records and interfaces.

Polyglot for Maventakari/polyglot-maven

Write Apache Maven POM files in Ruby, Groovy, Scala, YAML, Kotlin, Clojure, Java, or Atom instead of XML.

BIDMachBIDData/BIDMach

A CPU and GPU-accelerated machine learning library optimized for high-performance computing.

pulsarpuniverse/pulsar

A Clojure library providing Erlang-style concurrency with fibers, channels, and actors built on Quasar.

zt-execzeroturnaround/zt-exec

A Java library for executing external processes with improved stream handling, timeouts, exit code checking, and a fluent API.

Nitrite Databasedizitart/nitrite-database

An open-source NoSQL embedded document store for Java, supporting in-memory and file-based persistence with a simple API.

fastexceldhatim/fastexcel

A high-performance Java library for generating and reading large Excel files with minimal memory usage.

MariaDB4jMariaDB4j/MariaDB4j

A Java library that embeds MariaDB (MySQL-compatible) as a JAR, enabling database usage without external installation.

MCProtocolLibSteveice10/MCProtocolLib

A Java library for communicating with Minecraft clients and servers, enabling custom bots, clients, and servers.

EcmaScriptreactiverse/es4x

EcmaScript (JavaScript) language support for Eclipse Vert.x, enabling fast server-side JavaScript on the JVM.

camuslinkedin/camus

LinkedIn's previous generation Kafka to HDFS pipeline for batch data ingestion.