Top JAVA GitHub Repositories & Tools (2026)

HTML reports for Cucumber

jMetal: a framework for multi-objective optimization with metaheuristics

Are you a beginner eager to enhance your React JS skills? Look no further! This repository is the perfect platform for you to dive into the world of React development and contribute to open source during Hacktoberfest. @Hacktoberfest @ReactJS

This library provides an Ant task and a Maven plugin to create Debian packages from Java builds in a truly cross platform manner.

A small Java 8 library (string manipulation, BiStream, Structured Concurrency, SQL Templates)

Hibernate Search: full-text search for domain model

World Generation through a new Iris

Gerrit Code Review Tool Integration for the IntelliJ Platform

Port of a popular ruby faker gem written in kotlin. Generate realistically looking fake data such as names, addresses, banking details, and many more, that can be used for testing and data anonymization purposes.

DAO oriented database mapping framework for Java

oj! Algorithms - Open Source Java library for mathematics, linear algebra and optimisation. Pure Java, zero dependencies: fast matrices plus LP, QP and MIP solvers.

Mindmapping made simple: Host and create your own mindmaps. Share your mindmap sessions with your team and collaborate on mindmaps.

Java SDK for Milvus.

Modern Jira REST API client for JavaScript & TypeScript — Jira Cloud API v2/v3, Agile & Service Desk. Type-safe, tree-shakable, works in Node.js and browsers (ESM/CJS).

Flamingock brings Change-as-Code (CaC) to your entire stack. It applies versioned, auditable changes to the external systems your application depends on — such as schemas, message brokers, databases, APIs, cloud services, and any other external system your application needs.

BPMN-Process automation for everyone

Ahead of Time Data Repositories

eXist Native XML Database and Application Platform

Oracle Coherence Community Edition

OWASP VulnerableApp Project: Break it. Scan it. Reproduce it. Benchmark against it. Improve it.