java
Conductor is an event driven agentic workflow engine providing durable and highly resilient execution engine for applications and AI Agents .
Orchestrating distributed systems means wrestling with failures, retries, and state recovery. Conductor handles all of that so you don't have to.
Build Highly Reliable, Infinitely Scalable Applications Started at Netflix Engineering, built for high performance and planet scale. Cloud Agnostic, Language Agnostic and Deployment Agnostic.
Related contents:
Terminal UIs That Make Java Developers Smile 😊 A Java library for building modern terminal user interfaces.
TamboUI brings the TUI paradigms seen in things like Rust's ratatui or Go's bubbletea to the Java ecosystem.
Related contents:
Like Protobuf, without the pain. The single source of truth for your data types.
Skir is a declarative language for defining data types, constants, and APIs. Write your schema once in a .skir file and generate idiomatic, type-safe code in TypeScript, Python, Java, Go, C++, and more.
A minimal dependency implementation of Apache Parquet.
A parser for the Apache Parquet file format, optimized for minimal dependencies and great performance.
Related contents:
Square’s meticulous HTTP client for the JVM, Android, and GraalVM.
Related contents:
Java Evolved. Your Code Can Evolve Too!.
A collection of side-by-side code comparisons showing old Java patterns next to their clean, modern replacements — from Java 8 all the way to Java 25.
Spring Boot helps you to create Spring-powered, production-grade applications and services with absolute minimum fuss.
Related contents:
Tasty mocking framework for unit tests in Java. Most popular Mocking framework for unit tests written in Java.
Related contents:
Sampling CPU and HEAP profiler for Java featuring AsyncGetCallTrace + perf_events.
This project is a low overhead sampling profiler for Java that does not suffer from the Safepoint bias problem. It features HotSpot-specific API to collect stack traces and to track memory allocations. The profiler works with OpenJDK and other Java runtimes based on the HotSpot JVM.
Related contents:
Checkstyle is a development tool to help programmers write Java code that adheres to a coding standard. It automates the process of checking Java code to spare humans of this boring (but important) task. This makes it ideal for projects that want to enforce a coding standard.
The place to collaborate on an open-source implementation of the Java Platform, Standard Edition, and related projects.
Related contents:
FusionAuth HTTP client and server
A full featured, stand-alone, high-performance HTTP server and client written entirely in plain Java.
Related contents:
One command. 25 languages. Universal multi-language runner and smart REPL written in Rust.
A universal code runner and stateful REPL written in Rust. Execute Python, JavaScript, TypeScript, Go, Rust, C, C++, Java, Kotlin, Swift, and 15 more languages with a single command.
A tiny Kotlin Multiplatform library that provides an Omittable type to be used in cases where the absence of a value is semantically different from a null value.
Related contents:
AI-assisted SAST, SCA and Secrets Detection. Lightweight static analysis for many languages. Find bug variants with patterns that look like source code.
Semgrep is a fast, open-source, static analysis tool that searches code, finds bugs, and enforces secure guardrails and coding standards. Semgrep supports 30+ languages and can run in an IDE, as a pre-commit check, and as part of CI/CD workflows.
Related contents:
This open-source curriculum introduces the fundamentals of Model Context Protocol (MCP) through real-world, cross-language examples in .NET, Java, TypeScript, JavaScript, Rust and Python. Designed for developers, it focuses on practical techniques for building modular, scalable, and secure AI workflows from session setup to service orchestration.
an open-source, multilingual text-to-speech synthesis system written in pure java.
MaryTTS is an open-source, multilingual Text-to-Speech Synthesis platform written in Java. It was originally developed as a collaborative project of DFKI’s Language Technology Lab and the Institute of Phonetics at Saarland University. It is now maintained by the Multimodal Speech Processing Group in the Cluster of Excellence MMCI and DFKI.
Related contents:
An open-source, code-first Python or Java toolkit for building, evaluating, and deploying sophisticated AI agents with flexibility and control.
Agent Development Kit (ADK) is a flexible and modular framework for developing and deploying AI agents. While optimized for Gemini and the Google ecosystem, ADK is model-agnostic, deployment-agnostic, and is built for compatibility with other frameworks. ADK was designed to make agent development feel more like software development, to make it easier for developers to create, deploy, and orchestrate agentic architectures that range from simple tasks to complex workflows.
- Agent Development Kit (ADK) Python @ GitHub.
- Agent Development Kit (ADK) Java @ GitHub.
- Agent Development Kit (ADK) for Go @ GitHub.
Related contents:
Keep your code spotless.
Spotless can format <A ntlr | c | c# | c++ | css | flow | graphql | groovy | html | java | javascript | json | jsx | kotlin | less | license headers | markdown | objective-c | protobuf | python | scala | scss | shell | sql | typeScript | vue | yaml | anything> using <gradle | maven | sbt | anything>.
<DT> <A HREF="https://github.com/steipete/agent-rules" ADD_DATE="1750075227" PRIVATE="" TAGS="prompt-engineering,ai-agent,claude,cursor,open-source,foss,mit-licensed">Agent Rules</A><DD>Rules and Knowledge to work better with agents such as Claude Code or Cursor.A collection of reusable rules and knowledge documents for AI coding assistants like Claude Code and Cursor.
A Java PDF Library.
The Apache PDFBox® library is an open source Java tool for working with PDF documents. This project allows creation of new PDF documents, manipulation of existing documents and the ability to extract content from documents. Apache PDFBox also includes several command-line utilities. Apache PDFBox is published under the Apache License v2.0.
Related contents:
An open-source universal messaging library.
ZeroMQ (also known as ØMQ, 0MQ, or zmq) looks like an embeddable networking library but acts like a concurrency framework. It gives you sockets that carry atomic messages across various transports like in-process, inter-process, TCP, and multicast. You can connect sockets N-to-N with patterns like fan-out, pub-sub, task distribution, and request-reply. It's fast enough to be the fabric for clustered products. Its asynchronous I/O model gives you scalable multicore applications, built as asynchronous message-processing tasks. It has a score of language APIs and runs on most operating systems.
Chicory, a JVM native WebAssembly runtime.
Chicory is a JVM native WebAssembly runtime. It allows you to run WebAssembly programs with zero native dependencies or JNI. Chicory can run Wasm anywhere that the JVM can go. It is designed with simplicity and safety in mind. See the development section for a better idea of what we are trying to achieve and why.
Java Dynamic Reverse Engineering and Debugging Tool.
JDBG is a powerful Java debugger and reverse engineering tool that operates at runtime. It is attachable and is not limited by agent restrictions. JDBG leverages an injected DLL along with JNI and JVMTI to provide deep insight into Java applications.
OpenDAL represents Open Data Access Layer. Our vision is One Layer, All Storage.
OpenDAL (/ˈoʊ.pən.dæl/, pronounced "OH-puhn-dal") is an Open Data Access Layer that enables seamless interaction with diverse storage services.
OpenDAL's development is guided by its vision of One Layer, All Storage and its core principles: Open Community, Solid Foundation, Fast Access, Object Storage First, and Extensible Architecture.
Related contents:
A lightweight Java and Kotlin web framework.
Javalin is a very lightweight web framework for Kotlin and Java which supports WebSockets, HTTP2 and async requests. Javalin’s main goals are simplicity, a great developer experience, and first class interoperability between Kotlin and Java.
An open source Valkey client library that supports Valkey and Redis open source 6.2, 7.0 and 7.2. Valkey GLIDE is designed for reliability, optimized performance, and high-availability, for Valkey and Redis OSS based applications. GLIDE is a multi language client library, written in Rust with programming language bindings, such as Java and Python
Related contents:
The fully integrated standalone wiki and acceptance testing framework.
An open and free course to build your first mobile app, for complete beginners.
This course is an introduction to coding and programming through a simple project: creating a mobile app that runs natively on Android and iOS smartphones.
The Microsoft Graph software development kits (SDKs) are designed to simplify building high-quality, efficient, resilient applications that access Microsoft Graph. The SDKs include two components: a service library and a core library.
The service library contains models and request builders generated from Microsoft Graph metadata. The service library provides a rich, strongly-typed, and discoverable experience when working with the many datasets available in Microsoft Graph.
Missing Patch Scanner.
Vanir is a source code-based static analysis tool that automatically identifies the list of missing security patches in the target system. By default, Vanir pulls up-to-date CVEs from Open Source Vulnerabilities (OSV) together with their corresponding signatures so that users can transparently scan missing patches for an up-to-date list of CVEs.
Robot Framework is an open source automation framework for test automation and robotic process automation (RPA). It is supported by the Robot Framework Foundation and widely used in the industry.
Its human-friendly and versatile syntax uses keywords and supports extending through libraries in Python, Java, and other languages.
It integrates with other tools for comprehensive automation without licensing fees, bolstered by a rich community with hundreds of 3rd party libraries.
Build Reliable Backends 10x Faster, Scale to Millions with 1 Click.
DBOS is a serverless platform for building highly reliable applications. What takes days to build on AWS takes minutes on DBOS.
Related contents:
Fluent OpenStack client for Java.
OpenStack4j is a fluent OpenStack client that allows provisioning and control of an OpenStack deployment. This includes support for Identity, Compute, Image, Network, Block Storage, Telemetry, Data Processing as well as many extensions (LBaaS, FWaaS, Quota-Sets, etc)
Cloud Development Framework.
The AWS Cloud Development Kit (AWS CDK) is an open-source software development framework to define cloud infrastructure in code and provision it through AWS CloudFormation.
It offers a high-level object-oriented abstraction to define AWS resources imperatively using the power of modern programming languages. Using the CDK’s library of infrastructure constructs, you can easily encapsulate AWS best practices in your infrastructure definition and share it without worrying about boilerplate logic.
Meson® is a project to create the best possible next-generation build system.
Meson is an open source build system meant to be both extremely fast, and, even more importantly, as user friendly as possible.
The main design point of Meson is that every moment a developer spends writing or debugging build definitions is a second wasted. So is every second spent waiting for the build system to actually start compiling code.
Google's common Java, C++ and JavaScript library for parsing, formatting, and validating international phone numbers.
Desktop/Android/HTML5/iOS Java game development framework.
libGDX is a cross-platform Java game development framework based on OpenGL (ES) that works on Windows, Linux, macOS, Android, your browser and iOS.
open-source cryptographic APIs.
Welcome to the home of the Legion of the Bouncy Castle and its FIPS-certified open-source cryptographic APIs for Java and C#.
Kotlin is a modern but already mature programming language designed to make developers happier. It's concise, safe, interoperable with Java and other languages, and provides many ways to reuse code between multiple platforms for productive programming.
Apache MINA SSHD is a 100% pure java library to support the SSH protocols on both the client and server side. It does not aim at being a replacement for the SSH client or SSH server from Unix operating systems, but rather provides support for Java based applications requiring SSH support.
CloudBeaver is a web server which provides rich web interface. Server itself is a Java application, web part is written on TypeScript and React.
The Apache Thrift software framework, for scalable cross-language services development, combines a software stack with a code generation engine to build services that work efficiently and seamlessly between C++, Java, Python, PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, JavaScript, Node.js, Smalltalk, OCaml and Delphi and other languages.
A tool to detect bugs in Java and C/C++/Objective-C code before it ships
Infer is a static analysis tool - if you give Infer some Java or C/C++/Objective-C code it produces a list of potential bugs. Anyone can use Infer to intercept critical bugs before they have shipped to users, and help prevent crashes or poor performance.
A Java-based Sega Mega Drive/Genesis emulator. And other systems too.
Initially created as a Sega Megadrive/Genesis emulator and then evolved to emulate the following systems: Sega Megadrive/32X, Sega Master System/Game Gear, Sega Sg-1000, Colecovision, MSX v1, NES
buildGradleApplication is a Nix builder function for packaging Gradle applications.
buildGradleApplication drastically simplifies the integration of Gradle projects in the Nix ecosystem by defining a set of rules/constraints that a Gradle project must follow.
The Open Vulnerability Project is a collection of Java libraries and a CLI to work with various vulnerability data-sources (NVD, GitHub Security Advisories, CISA Known Exploited Vulnerablity Catalog, FIRST Exploit Prediction Scoring System (EPSS), etc.).
An API for asynchronous programming with observable streams.
ReactiveX is a combination of the best ideas from the Observer pattern, the Iterator pattern, and functional programming.
visualize, debug, get AI help for Python, Java, C, C++, and JavaScript.
Python Tutor helps you do programming homework assignments in Python, Java, C, C++, and JavaScript. It contains a unique step-by-step visual debugger and AI tutor to help you understand and debug code.
easy to use, completely free.
Violet is a UML editor with these benefits: Very easy to learn and use. Draws nice-looking diagrams. Completely free. Cross-platform. Violet is intended for developers, students, teachers, and authors who need to produce simple UML diagrams quickly
Dropwizard pulls together stable, mature libraries from the Java ecosystem into a simple, light-weight package that lets you focus on getting things done.
Dropwizard has out-of-the-box support for sophisticated configuration, application metrics, logging, operational tools, and much more, allowing you and your team to ship a production-quality web service in the shortest time possible.
jSQL Injection is a Java application for automatic SQL database injection.
An extensible multilanguage static code analyzer.
PMD is a source code analyzer. It finds common programming flaws like unused variables, empty catch blocks, unnecessary object creation, and so forth. It supports many languages. It can be extended with custom rules. It uses JavaCC and Antlr to parse source files into abstract syntax trees (AST) and runs rules against them to find violations. Rules can be written in Java or using a XPath query.
Supersonic Subatomic Java.
A Kubernetes Native Java stack tailored for OpenJDK HotSpot and GraalVM, crafted from the best of breed Java libraries and standards.
GraalVM is a high-performance JDK distribution designed to accelerate the execution of applications written in Java and other JVM languages along with support for JavaScript, Ruby, Python, and a number of other popular languages.
Related contents:
a mighty tiny command line interface.
Picocli aims to be the easiest way to create rich command line applications that can run on and off the JVM.
Picocli is a one-file framework for creating Java command line applications with almost zero code. It supports a variety of command line syntax styles including POSIX, GNU, MS-DOS and more. It generates highly customizable usage help messages that use ANSI colors and styles to contrast important elements and reduce the cognitive load on the user.
The Universal Plug-in System. make all software programmable. Extend from within. Extend anything with WebAssembly (wasm).
Run WebAssembly extensions inside your app. Use idiomatic Host SDKs for Go, Ruby, Python, Node, Rust, C, C++, OCaml, Haskell, PHP, Elixir/Erlang, .NET, Java, Zig & more (others coming soon).
A large-scale build tool. The successor to Buck. Ready for users ∈ {C++, Python, Rust, Erlang, OCaml}.
Buck2, a large scale, fast, reliable, and extensible build tool developed and used by Meta. Buck2 supports a variety of languages on many platforms.
Meson is an open source build system meant to be both extremely fast, and, even more importantly, as user friendly as possible.
The main design point of Meson is that every moment a developer spends writing or debugging build definitions is a second wasted. So is every second spent waiting for the build system to actually start compiling code.
Gearman provides a generic application framework to farm out work to other machines or processes that are better suited to do the work. It allows you to do work in parallel, to load balance processing, and to call functions between languages. It can be used in a variety of applications, from high-availability web sites to the transport of database replication events. In other words, it is the nervous system for how distributed processing communicates.