Java

Test library for specifying and asserting architecture rules.

Annotations and interfaces to express design and architecture concepts in code.

Simplifies integration of LLMs with unified APIs and a comprehensive toolbox.

Enables applications to interact with AI models and tools through a standardized interface (i.e. Model Context Protocol), supporting both synchronous and asynchronous communication patterns.

Library to use the OpenAI API (and compatible ones) in the simplest possible way.

Agent runtime with a Java SDK for building AI agents, supporting graph-based workflow orchestration, multi-agent coordination, and MCP/A2A protocols.

Provides fluent API for typesafe domain model validation and mapping. It uses annotations, code generation and a type safe DSL to make bean validation and mapping fast and easy.

Uses byte code manipulation for lightning-fast mapping. Supports annotations and API or XML configuration.

Code generator that simplifies mappings between different bean types, based on a convention-over-configuration approach.

Intelligent object mapping library that automatically maps objects to each other.

JavaBean-mapping framework that recursively copies (among other capabilities) data from one object to another.

Lambda and method handle-based mapping which requires code and not annotations if objects have different names.

Annotation processor-based bean mapper.

Encourages the creation of small, reusable modules consisting of code and resources.

Java 8 Jar & Android APK reverse engineering suite. (GPL-3.0-only)

Bytecode generation library.

Tries to simplify bytecode editing.

Provides low level bytecode generation.

Manipulate bytecode at runtime using real Java code.

Dynamically injects failure/latency at the bytecode level according to principles of chaos engineering.

High-performance, near-optimal caching library.

Annotation-based framework for parsing Git-like command-line arguments.

Reflectionless command line parser.

Includes features from modern shells like completion or history.

ANSI escape codes to format console output.

Aids the creation of full console-based applications.

Easy console text-GUI library, similar to curses. (LGPL-3.0-only)

Declarative, React-style TUI library for building terminal UIs as component trees with diff-based rendering, focus management, and themes.

Advanced console (and Swing) text user interface (TUI) library, with mouse-draggable windows, built-in terminal window manager, and sixel image support. Looks like Turbo Vision.

Provides Java APIs for interacting with Amazon Web Services.

Client libraries for accessing Google Cloud services from Java applications.

Static analysis of coding conventions and standards. (LGPL-2.1-or-later)

Catches common programming mistakes as compile-time errors.

Error Prone extensions: extra bug checkers and a large battery of Refaster templates.

Modern static analysis tool for verifying the correctness of code.

Source code analysis for finding bad coding practices.

Provides Alibaba's coding guidelines for PMD, IDEA and Eclipse.

Identifies and prioritizes God Classes and Highly Coupled classes.

Static analyzer for SonarQube & SonarLint. (LGPL-3.0-only)

Library for analyzing and transforming Java source code.

Static analysis of bytecode to find potential bugs. (LGPL-2.1-only)

Eliminates NullPointerExceptions with low build-time overhead.

Relies on offline (or static) bytecode instrumentation and class loading to collect code coverage metrics. (GPL-2.0-only)

Computes code coverage of new and modified code based on a provided diff, supporting JaCoCo and IntelliJ coverage engines.

JSR-269 code generator for algebraic data types.

Generates factory, service, and value classes.

Annotation processor for automatic DTO and Mapper generation with zero boilerplate.

Automatically generates the Builder pattern.

Discovers files that need generated code, updates automatically and writes to the source with a convenient API.

API to generate source files.

Yeoman source code generator for Spring Boot and AngularJS.

Maven plugin that automatically generates package-info.java files with JSpecify annotations (@NullMarked and @NullUnmarked), helping you manage nullness boundaries in your Java projects without manual boilerplate.

Companion builder class, withers and templates for Java records.

Maven plugin for generating Spring Boot CRUD applications from YAML/JSON specifications.

Java interface to OpenCV, FFmpeg, and much more.

Highly-available version-controlled service configuration repository based on Git, ZooKeeper and HTTP/2.

Configuration library supporting Java properties, JSON or its human optimized superset HOCON.

Configuration library with support for various configuration formats and transformations.

Twelve-factor configuration library which uses environment-specific files.

Simple, lightweight, yet powerful configuration library which supports resolution of properties from external sources such as files, databases, git repositories, and any custom sources, plus an extensible post-processing/conversion mechanism.

Gestalt offers a comprehensive solution to the challenges of configuration management. It allows you to source configuration data from multiple inputs, merge them intelligently, and present them in a structured, type-safe manner.

Annotation-based configuration system for Java and Kotlin.

Reduces boilerplate of properties.

Type-safe, composable configuration library with a focus on runtime clarity.

Includes an interface for the FlatZinc language, enabling it to execute MiniZinc models. (AGPL-3.0)

Performance-optimized, dependency-free and RFC 4180 compliant.

Jackson extension for reading and writing CSV.

Powerful CSV parser with support for Dozer, Joda-Time and Java 8.

One of the fastest and most feature-complete parsers. Also comes with parsers for TSV and fixed-width records.

Fast and persistent queue based on memory-mapped files.

Probabilistic data structure for computing union, intersection, and set cardinality in loglog space.

Persistent and immutable analogue of the Java Collections Framework.

Google's data interchange format.

Fast and efficient compressed bitmap.

Simple Binary Encoding, one of the fastest message formats around.

Lightning-fast, transactional, file-based FIFO.

Clean, lightweight protocol buffers.

Parse and build iCalendar RFC 5545 data models.

Determines the holidays for a given year, country/name and eventually state/region.

Additional date-time classes that complement those in JDK 8.

Advanced date and time library. (LGPL-2.1-only)

Determines the holidays for a given year, country/name and eventually state/region.

Implementation of the Tron Protocol, whic utilizes blockchains to develop decentralized applications.

Ultra-lightweight, JSR-330-compliant dependency injection library.

Extensions and utilities that enhance Google Guice.

Lightweight and opinionated framework that completes Dagger.

Lightweight and dynamic dependency injection framework.

Lightweight dependency injection framework. (LGPL-3.0-only)

JSR-330 runtime dependency injection using the JDK Class-File API.

Unlimited runtime class and resource redefinition. (GPL-2.0-only)

Parse, modify and generate Java code.

Symbol solver.

Re-energizes Java with powerful features like type-safe metaprogramming, structural typing and extension methods.

Ignores checked exceptions without bytecode manipulation. Can also be used inside Java 8 stream operations.

Enable infinite recursion using tail call optimization.

JVM modification that allows unlimited redefinition of loaded classes at runtime. (GPL-2.0-only)

Library that simplifies error handling by circumventing the issue that none of the functional interfaces in the Java Runtime is allowed by default to throw checked exceptions.

Circuit breaker design pattern for Dropwizard. (GPL-2.0-only)

Simple failure handling with retries and circuit breakers.

Highly scalable in-memory datagrid with a free open-source version.

Functional fault tolerance library.

High-performance reverse proxy server with specialized session management and credential replay functionality.

Embeddable Cluster-Membership library based on SWIM and gossip protocol.

Gateway service that provides dynamic routing, monitoring, resiliency, security, and more.

Simple but complete implementation of the JTA 1.1 API.

Delivers high performance and easy to use distributed transaction services under a microservices architecture.

Binary artifact management toolkit which hosts them on the file system or S3.

Simple and powerful packaging and deployment. A fat JAR on steroids, or a "Docker for Java" that supports JVM-optimized containers.

System for deploying Java applications to end-user computers and keeping them up to date. Developed as an alternative to Java Web Start.

Maven and Gradle plugin which provides an easy way to package Java applications in native Windows, macOS or GNU/Linux executables, and generate installers for them.

Builds optimized runtimes over HTTP.

Packs JARs, assets and the JVM for native distribution on Windows, Linux and macOS.

Maven plugin for making self-executing JARs.

High performance library to read and write large Excel (XLSX) worksheets.

Annotation-based API for reading data from Excel sheets into POJOs with focus on reduced overhead.

Library for reading and writing Excel and CSV files with annotation-based mapping, streaming support, and built-in validation.

Trading bot framework.

Platform for trading venues.

Low-latency financial information exchange.

Integration with the Square API.

Integration with the Stripe API.

Library for technical analysis.

Concolic unit testing engine. Automatically generates unit tests using formal methods.

JVM formal verification tool containing a model checker and more. Created by NASA.

Monad and stream utilities, comprehensions, pattern matching, functional extensions for all JDK collections, future streams, trampolines and much more.

Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching and morphisms. (GPL-3.0-only)

Gatherers library for Java Stream API. Gatherers can enhance streams with custom intermediate operations.

Collection of stream utilities.

Enhances Java 8 Streams.

Stream API Collectors for parallel processing with custom thread pools, designed for I/O-heavy workloads.

Extension to Java 8 that aims to fix gaps in lambda by providing numerous missing types and a rich set of sequential Stream API additions.

High-level 2D game engine with built-in physics based on Swing.

Vulkan, OpenGL ES2 and GLFW Memory Allocator bindings.

JavaFX library for adding mapping and GIS functionality to desktop apps.

GeoHash utilities in Java.

Road-routing engine. Used as a Java library or standalone web service.

Map rendering based on OpenStreetMap data. (LGPL-3.0-only)

General-purpose spatial/geospatial library.

Modern Java UI library for both desktop and web.

Lightwieght declarative DSL for rapid development of Swing applications.

Data structures and utility methods that are common in high-performance applications.

Collections framework inspired by Smalltalk.

Concurrency tools currently missing from the JDK.

Carefully designed extension of the Java Collections Framework with primitive specializations and more.

Asynchronous HTTP and WebSocket client library.

HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.

Pluggable HTTP transport abstraction with support for java.net.HttpURLConnection, Apache HTTP Client, Android, Google App Engine, XML, Gson, Jackson and Protobuf.

HTTP client extensions library.

Client-side IPC library that is battle-tested in the cloud.

Client-side response routing for Spring's RestTemplate.

Simplified, lightweight HTTP client library.

Builds hypermedia-friendly objects according to HAL specification.

JSON-LD implementation.

Library for the Siren specification.

Standalone and Spring support for building hypermedia-based APIs using HAL, HAL FORMS, Collection+JSON, ALPS and UBER.

Generates QR Code, DataMatrix, and other 1D/2D barcodes as vector (PDF, EPS, SVG) and raster (PNG, BMP, JPG) images with DPI awareness, high precision, and CMYK color model support.

Simple, efficient and hardware-accelerated image-scaling library implemented in pure Java 2D.

JNA wrapper for Tesseract OCR API.

High-quality thumbnail generation library.

Collection of plugins that extend the number of supported image file formats.

Multi-format 1D/2D barcode image processing library.

Library that compares 2 images with the same sizes and shows the differences visually by drawing rectangles. Some parts of the image can be excluded from the comparison.

Comprehensive bindings for libvips, using Java's "Foreign Function & Memory" API.

Immutable, functional, and performant JVM library for manipulation of images.

ClassGraph (formerly FastClasspathScanner) is an uber-fast, ultra-lightweight, parallelized classpath scanner and module scanner for Java, Scala, Kotlin and other JVM languages.

jOOR stands for jOOR Object Oriented Reflection. It is a simple wrapper for the java.lang.reflect package.

ReflectASM is a very small Java library that provides high performance reflection by using code generation.

Reflections scans your classpath, indexes the metadata, allows you to query it on runtime and may save and collect that information for many modules within your project.

Job scheduling library which utilizes lambdas for fire-and-forget, delayed and recurring jobs. Guarantees execution by single scheduler instance using optimistic locking. Has features for persistence, minimal dependencies and is embeddable.

Feature-rich, open source job scheduling library that can be integrated within virtually any Java application.

Lightweight framework to simply define jobs, define triggers and start the scheduler.

Simple library with minimal footprint and straightforward API.

Persistent and cluster-friendly scheduler.

Set up batch jobs with simple processing pipelines. Records are read in sequence from a data source, processed in pipeline and written in batches to a data sink.

Makes sure that your scheduled tasks are executed at most once at the same time. If a task is being executed on one node, it acquires a lock which prevents execution of the same task from another node or thread.

JSON library with advanced compile time databinding.

Serializes objects to JSON and vice versa. Good performance with on-the-fly usage.

High-performance JSON parser, 2x faster than Jackson.

Set of Jackson modules for Java 8 datatypes and features.

Open-source Jackson module to support JSON serialization and deserialization of JavaMoney data types.

Similar to GSON, but offers performance gains if you need to instantiate the library more often.

Convert Java to JSON/TOON and back. Supports complex object graphs, cyclic references, and TOON format for 40-50% LLM token savings.

Modern JSON library, less opinionated and uses built-in types like List and Map.

Binding layer between classes and JSON documents similar to JAXB.

Very fast processor with no additional dependencies and full data binding.

JSON to JSON transformation tool.

Extract data from JSON using XPATH-like syntax.

Streaming JsonPath processor dedicated to processing big and complicated JSON data.

JSON parsing and serializing library based on Jackson's streaming API. Outperforms GSON & Jackson's library.

Downstream version of OpenJDK optimized for online e-commerce, financial, logistics applications.

Polyglot embeddable JVM. (GPL-2.0-only WITH Classpath-exception-2.0)

High performance, enterprise-calibre, flexibly licensed, openly-governed cross-platform JVM extending and augmenting the runtime technology components from the Eclipse OMR and OpenJDK project.

VM with non-blocking, concurrent GC for iOS. (GPL-2.0-only WITH Classpath-exception-2.0)

Microsoft Build of OpenJDK, Free, Open Source, Freshly Brewed!

SAP's no-cost, rigorously tested and JCK-verified OpenJDK friendly fork. (GPL-2.0-only WITH Classpath-exception-2.0)

API designed around structured logging, rich context, and conditional logging. There are Logback and Log4J2 implementations, but Echopraxia's API is completely dependency-free, meaning it can be implemented with any logging API.

Extensible, open-source library for HTTP request and response logging.

Enables logging for all JDBC transactions without changes to the code.

Collection of libraries that build on top of OpenTracing and provide extensions and plugins to existing instrumentations.

Flogger is a fluent logging API for Java. It supports a wide variety of features, and has many benefits over existing logging APIs.

Seamlessly integrate with remote deep learning and language models programmatically.

Algorithms for pre-processing, classification, regression, and clustering with support for multi-threaded execution. (GPL-3.0-only)

CLI tool to transpile models into native code.

A lightweight, platform independent, OpenCL accelerated nd-array/tensor library.

Framework for building real-time, large-scale machine learning applications. Includes end-to-end applications for collaborative filtering, classification, regression, and clustering.

Cloud native streaming and complex event processing engine.

Statistical Machine Intelligence and Learning Engine provides a set of machine learning algorithms and a visualization library.

Efficient, reliable, unicast and multicast message transport.

AutoMQ is a cloud-native, serverless reinvented Kafka that is easily scalable, manage-less and cost-effective.

Simple, lightweight, yet FAST messaging library for decoupling messages (requests and events) and message handlers.

Simple publish/subscribe event bus.

Implementation of ZeroMQ.

Provides a RESTful API on top of Kafka.

RabbitMQ client.

Cross-platform XMPP client library.

NATS client.

Asynchronous RPC/REST client/server library built on top of Java 8, Netty, HTTP/2, Thrift and gRPC.

Client for the Consul API: a distributed, highly available and datacenter-aware registry/discovery service.

REST-based service registry for resilient load balancing and failover.

Wrapping of the Discord REST API and its WebSocket events.

Modernized version of a Java-based implementation of the New Typesetting System, which was heavily based on Donald E. Knuth's original TeX.

Client provides access to the full Kubernetes & OpenShift REST APIs via a fluent DSL.

Java libraries for using OpenAI's GPT-3 API.

Flow control component enabling reliability, resilience and monitoring for microservices.

Ultra-fast, SQL-like queries on Java collections.

Implementation and explanation of the most common design patterns.

Feature Flags for Java.

No-nonsense implementation of FizzBuzz made by serious businessmen for serious business purposes. (No explicit license)

Wrapper for the IP2Location.io Geolocation API and the IP2WHOIS domain WHOIS API.

A small library that contains a representation object of ISBN-10 and ISBN-13 and tools to parse, validate and format one.

Java-to-Objective-C translator for porting Android libraries to iOS.

Framework for building chatbots. (GPL-3.0-only)

An auto-generated emoji library that provides type-safe direct access to emojis and alias support for Discord, Slack, GitHub and many more features.

In-memory file system.

Source transpiler to TypeScript/JavaScript.

Analogue of Gradle Wrapper for Maven, allows building projects without installing maven.

Open-source, reverse-proxy framework.

Lightweight, small and customizable FTP server.

High performance HTTP proxy atop Netty's event-based networking library.

Popular Java 8 guide.

Detect uses of legacy Java APIs.

Browser extension which allows to navigate through code on GitHub more efficiently.

Small utility library for using handlers and commands with pipelines.

Extensions for Maven 3.3.1+ that allows writing the POM model in dialects other than XML.

RR4J is a tool that records java bytecode execution and later allows developers to replay locally.

Mailing with a clean and fluent API.

Framework for fragment-based message processing. (Apache-2.0 OR LGPL-3.0-or-later)

Tools for resolving generic types.

Library for using built-in and external webcams directly in Java.

Processes XML by using annotations or XPath within code.

Obfuscation via renaming and shrinking.

JUnit 5 extension pack, pushing the frontiers on Jupiter.

Simple wrapper for the org.w3c.dom package, to allow for fluent XML document creation and manipulation with an API inspired by jQuery.

Reactive, type-safe framework for Telegram bots based on Spring Boot 3 and Java 21.

Library for the Svix API to send webhooks and verify signatures.

Simple, privacy-focused API monitoring, analytics and request logging for Spring Boot apps.

Combines the power of AOP with monitoring and/or logging tools.

Spring Boot Actuator extension providing application startup and runtime metrics including JVM uptime, memory usage, and CPU load.

Modern monitoring & analytics.

Expose metrics via JMX or HTTP and send them to a database.

Out of the box monitoring of Failsafe Circuit Breaker in Spring-Boot environment.

Real-time monitoring system with custom-monitor and agentless.

Dynamic and observable thread pool framework.

Jaeger client.

Performance monitoring and profiling.

Connect to multiple JVMs and query them for their attributes via JMX. Its query language is based on JSON, which allows non-Java programmers to access the JVM attributes. Supports different output writes, including Graphite, Ganglia, and StatsD.

Vendor-neutral metrics/observability facade for the most popular metrics/observability libraries.

Vendor-neutral distributed tracing facade for the most popular tracer libraries.

Remote developer console from the browser for Java 8 via bytecode injection.

Instrument, generate, collect, and export telemetry data to help you analyze your software’s performance and behavior.

Open-source APM tool.

Provides a multi-dimensional data model, DSL, autonomous server nodes and much more.

Integration with Sentry, an application error tracking and performance analysis platform.

Performance monitor with distributing transaction tracing for JVM apps.

Open-source performance monitoring and transaction tracing for JVM apps.

Lightweight platform monitoring tool for Java VMs.

Converts bytecode to OpenCL which allows execution on GPUs.

Provides efficient and easy access to native C++.

Work with native libraries without writing JNI. Also provides interfaces to common system libraries.

Work with native libraries without writing JNI. Also provides interfaces to common system libraries. Same goals as JNA, but faster, and serves as the basis for the upcoming Project Panama.

Native library loader for extracting and loading native libraries from Java.

Provides common annotators for plain text input. (Research and Academic Use License)

Java hyphenation library with iterator-like interface. Can be used out-of-the box - dictionaries for multiple languages are bundled in.

Client for server-sent events (SSE).

Integrates standard Java web-related APIs with Quasar fibers and actors.

High-performance RPC framework.

RPC framework based on protobuf and HTTP/2.

Provides a clean and simple API for efficient TCP and UDP client/server network communication using NIO and Kryo.

Easy-to-use, annotation-based library for creating Thrift clients and serializable types.

Framework built on Netty with APIs tailored to specific protocols and support for multiple programming paradigms.

Programmatically use SSH, SCP or SFTP.

Implements a ByteChannel interface over SSLEngine, enabling easy-to-use (socket-like) TLS.

Represent, parse and encode URNs, as in RFC 2141. (GPL-3.0-only)

High throughput data ingestion logger to Fluentd and Fluent Bit.

Database access framework that verifies and generates source code at compile time using annotation processing as well as native SQL templates called two-way SQL.

Couples objects with stored procedures or SQL statements.

A powerful enhanced toolkit of MyBatis for simplifying development.

ActiveRecord ORM for rapid development and convention over configuration.

Language-natural persistence layer.

Simple database and CSV mapper.

Code-first dynamic ORM for MyBatis with runtime schema modification.

A highly configurable 3D A* pathfinding library that uses specific optimizations for high performance.

Simplifies JasperReports. (LGPL-3.0-only)

XML/XHTML and CSS 2.1 renderer. (LGPL-2.1-or-later)

Properly supports modern PDF standards based on flyingsaucer and Apache PDFBox.

Open-source iText fork. (LGPL-3.0-only & MPL-2.0)

Extracts tables from PDF files.

Low-overhead, bias-free sampling profiler.

Logs and records platform JVM stalls.

Analyze the JIT compiler optimisations made by the HotSpot JVM.

Utilities for latency measurement and reporting.

Memory leak diagnostics that orchestrates jcmd, jmap, jstat, JFR, Eclipse MAT, and async-profiler into a structured investigation workflow with confidence-based verdicts.

Java agent for line-level execution frequency analysis to identify algorithmic bottlenecks.

Fast, lightweight and productive microservices framework with built-in security.

Open-source business application platform for rapid configuration/development of CRM, ERP, LMS and other applications.

Byte Code Engineering Library - analyze, create, and manipulate Java class files.

Easy-to-use wrappers around the Java reflection and introspection APIs.

Redesign of Commons BeanUtils.

Bean Scripting Framework - interface to scripting languages, including JSR-223.

Chain of Responsibility pattern implementation.

Find Class interfaces, methods, fields, and annotations without loading.

Command-line arguments parser.

Redesign of Commons CLI.

General encoding/decoding algorithms, e.g. phonetic, base64 or URL.

Extends or augments the Java Collections Framework.

Defines an API for working with tar, zip and bzip2 files.

Reading of configuration/preferences files in various formats.

Commons-Convert aims to provide a single library dedicated to the task of converting an object of one type to another.

Component for reading and writing comma separated value files.

Alternative invocation mechanism for unix-daemon-like java code.

Database connection pooling services.

JDBC helper library.

XML-to-Java-object mapping utility.

Library for sending e-mail from Java.

API for dealing with external process execution and environment management in Java.

File upload capability for your servlets and web applications.

Java library inspired by the UNIX find command.

Java library for working with flat data structures.

Function that can be manipulated as an object, or an object representing a single, generic function.

General purpose graph APIs and algorithms.

Adds the feature of localized message bundles that consist of one or many localized texts that belong together.

Id is a component used to generate identifiers.

Image library.

Collection of I/O utilities.

Continuation implementation to capture the state of the application.

Java Compiler Interface.

Java Caching System.

XML based scripting and processing engine.

Expression language which extends the Expression Language of the JSTL.

JNet allows to use dynamically register url stream handlers through the java.net API.

Utilities for manipulating Java Beans using the XPath syntax.

Provides extra functionality for classes in java.lang.

Wrapper around a variety of logging API implementations.

Lightweight, self-contained mathematics and statistics components.

Monitoring aims to provide a simple but extensible monitoring solution for Java applications.

Nabla provides automatic differentiation classes that can generate derivative of any function implemented in the Java language.

Collection of network utilities and protocol implementations.

Object-graph navigation language.

Interface to signing and verifying data using OpenPGP.

Small framework for microbenchmark clients, with implementations for Commons DBCP and Pool.

Provides a set of pipeline utilities designed around work queues that run in parallel to sequentially process data objects.

Generic object pooling component.

Library for creating dynamic proxies.

Common implementation of RDF 1.1 that could be implemented by systems on the JVM.

Commons Rng provides implementations of pseudo-random numbers generators.

Implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine.

Framework to define validators and validation rules in an xml file.

Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.

Provides an easy way to enhance (weave) compiled bytecode.

Convenient API around Apache Commons Exec.

Provides a unified API to Apache Commons Exec and ProcessBuilder.

Stops processes started from Java or the system processes via PID.

Provides a standard for asynchronous stream processing with non-blocking backpressure.

A framework for building non-blocking applications on the JVM, providing support for reactive programming.

Allows for composing asynchronous and event-based programs using observable sequences.

Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.

Convenient, extensible microservices plugin system for Spring & Spring Boot. With more than 30 plugins and growing, it supports both micro-monolith and pure microservices styles.

Framework for building robust, scalable RESTful architectures using typesafe bindings and asynchronous, non-blocking IO with an end-to-end developer workflow that promotes clean practices, uniform interface design and consistent data modeling.

Allows generation of API client libraries, SDKs, server stubs, documentation and configuration automatically given an OpenAPI Spec.

Pioneering framework with powerful routing and filtering capabilities, and a unified client and server API.

Automates the generation of API documentation using Spring Boot projects.

Thin wrapper on the JBoss Netty HTTP stack that provides scaling and performance.

Scientific charting library with focus on performance optimised real-time data visualisation at 25 Hz update rates for large data sets.

Modular, light and easy graph framework for theoretic algorithms.

Graph library that provides mathematical graph-theory objects and algorithms.

Library for visualizing (mainly Swing) and interacting with node-edge graphs.

jSciPy is a Java library designed for scientific computing, offering functionalities inspired by popular scientific computing libraries. It currently provides modules for signal processing, including Butterworth filters, peak finding algorithms, and an RK4 solver for ordinary differential equations.

Library for creating, manipulating and solving Boolean and Pseudo-Boolean formulas.

Library for geophysical scientific computation, visualization and digital signal analysis.

Provides a versatile two-dimensional memory efficient tabular data structure called a DataFrame to enable efficient in-memory analytics for scientific computing on the JVM.

Generates a wide variety of 3D charts that can be displayed with Swing and JavaFX or exported to PDF, SVG, PNG and JPEG. (GPL-3.0-only)

Includes a data-frame, an embedded column store, and hundreds of methods to transform, summarize, or filter data.

Light-weight library for plotting data. Many customizable chart types are available.

Simple and light full text indexing and searching library.

High-level SSL configuration builder for configuring HTTP clients and servers with SSL/TLS.

Detects publicly disclosed vulnerabilities contained within a project's dependencies.

Runtime application that repels application security risks included in the OWASP Top 10, including SQL injection, cross-site scripting, cross-site request forgery, data tampering, and brute force attacks.

JSON web token for Java and Android.

Easily create and parse JSON Web Tokens and create customized JWT validators using a fluent API.

JSON Web Key Set parser.

Binding for the Networking and Cryptography (NaCl) library.

System for distributing and managing secrets.

Advanced password strength estimation.

Access management solution that includes authentication, SSO, authorization, federation, entitlements and web services security.

One-time password generator library according to RFC 4226 (HOTP) and RFC 6238 (TOTP).

Security engine.

User-friendly cryptographic library that supports Argon2, Bcrypt, Scrypt, PBKDF2 and various other cryptographic hash functions.

Fluent Builder API for JCA and JSSE classes and especially X.509 certificates.

Multi-platform high-level cryptographic library provides easy-to-use encryption for protecting sensitive data: secure messaging with forward secrecy, secure data storage (AES256GCM); suits for building end-to-end encrypted applications.

Provides a simple and misuse-proof API for common cryptographic tasks.

CLI tool and library for extracting and exporting server certificates from HTTPS endpoints.

Memory-efficient serialization library that can access serialized data without unpacking and parsing it.

JDK-compatible, high-performance object graph serialization.

Blazing fast object graph serialization framework powered by JIT and zero-copy.

Fast and efficient object graph serialization framework.

Efficient binary serialization format.

Serializing objects in the PHP serialization format.

Implementation of Pug (formerly known as Jade).

Extendable template engine embedded into Maven/JavaDoc, supporting multiple extensions (Groovy, Ruby, JavaScript, JShell, PlantUml) with support for snippet handling.

Typesafe Mustache templating engine.

Compiles to classes, and uses an easy syntax, several features to make development easier and provides fast execution and a small footprint.

Modular, configurable and fully tested template engine.

Optimized, memory efficient and speedy template engine producing statically typed, plain objects.

Template engine for generating source code, web pages, emails, or any other formatted text output.

Set of test framework extensions (JUnit 4, JUnit 5, Spock) to enhance the testing of CDI components via Weld. Supports Weld 5.

JUnit extension for easy and efficient testing of CDI components.

Fluent assertions that improve readability.

Allows to troubleshoot production issues for applications without modifying code or restarting servers.

Rate limiting library based on token-bucket algorithm.

Collection of object-oriented primitives.

Generates postman collection, environment and integration tests from java code.

Java/JavaFX tool capable of powerful ETL and data visualization.

Regular expression engine that uses deterministic finite automata. It supports some Perl-style features and yet retains linear matching time, and also offers set operations.

Bulk data loader that helps data transfer between various databases, storages, file formats, and cloud services.

Micro library to watch for directory file system changes, simplifying java.nio.file.WatchService.

Cross-platform for visualizing and manipulating large graph networks. (GPL-3.0-only)

Collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and more.

Generate Javadoc from your maven/gradle project and deploy it automatically on GitHub Page.

Library that helps with constructing difficult regular expressions.

Java scope functions inspired by Kotlin.

Provides simple APIs to access any Amazon S3-compatible object storage server.

Lightweight library that helps you handling semantic versioning with different modes.

Port of Underscore.js functions.

Generate Javadoc from your maven/gradle project and deploy it automatically on GitHub Page.

Zero-dependency, high-performance utilities featuring Converter (universal type conversion), DeepEquals, CaseInsensitiveMap, TTLCache, CompactMap, MultiKeyMap, and object graph traversal.

Reads a Java project and generates a structured context file so AI tools can understand and help plan the codebase.

Zero-dependency refinement types for Java 8+ with type-safe wrappers covering numerics, strings, and collections.

Type-safe, AST-based Regex Builder focused on readability and ReDoS prevention.

Java Version Manager inspired by nvm. Supports macOS, Linux and Windows.

Java Version Manager inspired by rbenv. Can configure globally or per project. Tested on Debian and macOS.

Java Version Manager inspired by RVM and rbenv. Supports UNIX-based platforms and Windows.

Simple and lightweight web crawler.

Scalable crawler with downloading, url management, content extraction and persistent.

Lightweight, modular framework that aims to be elegant and simple.

Opinionated web framework which is built around the concepts of True Object-Oriented Programming and immutability.

Annotation-Driven Low-Code & JPA Visualization

Lightweight, pluggable framework for building Java applications with CLI, HTTP, and modular extension support.

Compact and efficient workflow and business process management platform.

Integration testing, API mocking and faking, and code coverage.

DSL for synchronizing asynchronous operations.

Toolkit for testing multi-threaded and asynchronous applications.

Native bindings for Hoverfly, a proxy which allows you to simulate HTTP services.

DSL that combines API test-automation, mocks and performance-testing making testing REST/HTTP services easy.

DSL for easy testing of REST/HTTP services.

Test across REST-API, Graph QL, Browser, Database, CLI and Business Logic with consistent set of matchers and concepts.

Provides a way to describe features in a plain language which customers can understand.

Collection of Gherkin steps for REST-service testing using Cucumber.

Follows a Jasmine-like syntax.

Aims to provide a fluent API to write tests in long and descriptive sentences that read like plain English.

Automated Acceptance testing and reporting library that works with Cucumber, JBehave and JUnit to make it easier to write high quality executable specifications.

Code-first BDD framework for Java and Kotlin that generates interactive HTML reports and sequence diagrams from test code.

Supports generating test data or combining scenarios for parameterized tests.

Sets up beans from YAML fixtures.

Modern fake data generator forked from Java Faker.

Generates fake objects from a template.

Fake data generator.

Automates data setup in unit tests by generating fully-populated, reproducible objects. Includes JUnit 5 extension.

JUnit test runner and plugins for running JUnit tests with pseudo-randomness.

Port of Ruby's fake data generator.

Another fake data generator.

JMock is a high-performance data generation and simulation component library implemented in Java.

Load tests with JMeter as simple as a JUnit test.

JUnit extension for easy and efficient testing of CDI components.

Consumer-driven contract testing.

Browser automation framework and ecosystem.

Load testing tool designed for ease of use, maintainability and high performance.

Simplifies testing for XML output.

Library that simplifies JSON comparison in tests.

Captures console output for unit testing purposes.

TestNG-like data provider/runner for JUnit.

Captures log entries and provides assertions for unit and integration testing.

Reports whether instances of a given class are immutable.

Tests if a request/response matches a given RAML definition.

Snapshot testing (inline and on disk).

Multi-approach framework for test steps managing.

Provides throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

Captures log entries for unit testing purposes.

Real-time test execution control via Google Spreadsheet, enabling instant toggle without code changes.

Mocking framework that lets you write tests with a clean and simple API.

Concise web services for stubs and mocks.

Mocks static methods, constructors, final classes and methods, private methods, and removal of static initializers.

EasyMock is a Java library that provides an easy way to use Mock Objects in unit testing.