Java

FregeFrege/frege

Frege is a Haskell-like purely functional programming language that compiles to Java and runs on the JVM.

Frege vs. HaskellFrege/frege

Frege is a Haskell-like purely functional programming language that compiles to Java bytecode and runs on the JVM.

Light-4jnetworknt/light-4j

A fast, lightweight, cloud-native microservices framework for Java with built-in cross-cutting concerns.

Light-4Jnetworknt/light-4j

A fast, lightweight, cloud-native microservices framework for Java with built-in cross-cutting concerns.

ArchUnitTNG/ArchUnit

A Java library for specifying and testing architecture rules in plain Java unit tests.

kubernetes-clientfabric8io/kubernetes-client

A Java client library providing a fluent DSL to interact with Kubernetes and OpenShift REST APIs.

Apache Heron (incubating)apache/incubator-heron

Apache Heron is a real-time, distributed, fault-tolerant stream processing engine developed by Twitter.

deequawslabs/deequ

A library built on Apache Spark for defining unit tests to measure data quality in large datasets.

Schema Spyschemaspy/schemaspy

A database metadata analyzer that generates interactive HTML documentation and entity-relationship diagrams.

ThreeTen Android BackportJakeWharton/ThreeTenABP

An Android-optimized backport of Java 8's java.time API for handling dates and times.

Scaldingtwitter/scalding

A Scala API for Cascading that simplifies writing Hadoop MapReduce jobs with Scala integration.

osoosohq/oso

A batteries-included framework for building authorization in your application with a declarative policy language.

ICUunicode-org/icu

A mature, widely-used set of C/C++ and Java libraries providing Unicode and globalization support for software applications.

KeyBoxskavanagh/KeyBox

A modern, web-based SSH console and key management tool that functions as a secure bastion host.

WorldEditEngineHub/WorldEdit

An in-game Minecraft map editor with selections, schematics, copy/paste, brushes, and scripting for creative building and server management.

Simple Binary Encodingreal-logic/simple-binary-encoding

A high-performance binary message codec for low-latency financial applications, with multi-language support.

Android Priority Job Queueyigit/android-priority-jobqueue

A deprecated Android job queue library for scheduling background tasks with prioritization, persistence, and network awareness.

MCP Java SDKmodelcontextprotocol/java-sdk

The official Java SDK for building and consuming Model Context Protocol servers and clients, enabling Java apps to interact with AI models.

Swiss Java Knifearagozin/jvm-tools

A command-line Swiss Army knife for JVM diagnostics, troubleshooting, and profiling using JMX, JVM attach, and perf counters.

DGS FrameworkNetflix/dgs-framework

A GraphQL server framework for Spring Boot with annotation-based programming and comprehensive tooling.

JMX exporterprometheus/jmx_exporter

A collector that captures JMX MBean values and exposes them as Prometheus metrics.

jitwatchAdoptOpenJDK/jitwatch

A log analyzer and visualizer for the Java HotSpot JIT compiler, enabling inspection of inlining, hot methods, bytecode, and assembly.

Heritrixinternetarchive/heritrix3

An open-source, extensible, web-scale, archival-quality web crawler from the Internet Archive.

Heritrix Q&Ainternetarchive/heritrix3

An open-source, extensible, web-scale, archival-quality web crawler from the Internet Archive.

TruffleRubyoracle/truffleruby

A high-performance Ruby implementation built on GraalVM, offering parallel execution and polyglot interoperability.

Agronareal-logic/Agrona

A Java library of high-performance data structures and utilities for low-latency applications.

JailerWisser/Jailer

A tool for database subsetting and relational data browsing, creating consistent slices and enabling navigation via foreign keys.

requeryrequery/requery

A modern SQL-based object mapping and query library for Java, Kotlin, and Android with RxJava and Java 8 support.

Synthea Patient Generatorsynthetichealth/synthea

An open-source synthetic patient population simulator that generates realistic (but not real) patient data and health records in multiple formats.

HugeGraphapache/incubator-hugegraph

A fast, highly-scalable graph database supporting over 10 billion vertices and edges with OLTP capabilities and dual Gremlin/Cypher query language support.

shogunshogun-toolbox/shogun

A unified and efficient machine learning toolbox with C++ core and multi-language interfaces, developed since 1999.

Apache Netbeansapache/netbeans

An open-source integrated development environment (IDE) and application framework for Java, PHP, and other languages.

JavaMelodyjavamelody/javamelody

Monitoring solution for Java and Java EE applications in QA and production environments.

YUI Compressoryui/yuicompressor

A JavaScript and CSS compressor that removes whitespace, comments, and safely obfuscates local variables for optimal file size reduction.

ClassGraphclassgraph/classgraph

An ultra-fast parallelized classpath and module scanner for JVM languages that indexes class metadata without loading classes.

JobRunrjobrunr/jobrunr

A Java library for easy, reliable background job processing with persistent storage, using Java 8 lambdas.