An open API service indexing awesome lists of open source software.

awesome-java

A curated list of awesome frameworks, libraries and software for the Java programming language.
https://github.com/eric-erki/awesome-java

Last synced: 3 days ago
JSON representation

  • Projects

    • Bean Mapping

      • dOOv - 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.
      • Dozer - Mapper that copies data from one object to another using annotations and API or XML configuration.
      • JMapper - Uses byte code manipulation for lightning-fast mapping. Supports annotations and API or XML configuration.
      • MapStruct - Code generator that simplifies mappings between different bean types, based on a convention-over-configuration approach.
      • ModelMapper - Intelligent object mapping library that automatically maps objects to each other.
      • Orika - JavaBean-mapping framework that recursively copies (among other capabilities) data from one object to another.
      • reMap - Lambda and method handle-based mapping which requires code and not annotations if objects have different names.
      • Selma - Annotation processor-based bean mapper.
      • dOOv - 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.
      • Selma - Annotation processor-based bean mapper.
    • Build

      • Buck - Encourages the creation of small, reusable modules consisting of code and resources.
      • Gradle - Incremental builds programmed via Groovy instead of declaring XML. Works well with Maven's dependency management.
      • Bazel - Tool from Google that builds code quickly and reliably.
    • Bytecode Manipulation

      • bytecode-viewer - Java 8 Jar & Android APK reverse engineering suite. (GPL-3.0-only)
      • cglib - Bytecode generation library.
      • Javassist - Tries to simplify bytecode editing.
      • Mixin - Manipulate bytecode at runtime using real Java code.
      • Perses - Dynamically injects failure/latency at the bytecode level according to principles of chaos engineering.
      • ASM - All-purpose, low-level bytecode manipulation and analysis.
      • Perses - Dynamically injects failure/latency at the bytecode level according to principles of chaos engineering.
    • Caching

      • Caffeine - High-performance, near-optimal caching library.
    • CLI

      • ASCII Table - Library to draw tables in ASCII.
      • Airline - Annotation-based framework for parsing Git-like command-line arguments.
      • args4j - Small library to parse command-line arguments.
      • Jansi - ANSI escape codes to format console output.
      • Java ASCII Render - Graphical primitives for the console.
      • JCommander - Command-line argument-parsing framework with custom types and validation via implementing interfaces.
      • args4j - Small library to parse command-line arguments.
      • JLine - Includes features from modern shells like completion or history.
      • JOpt Simple - Fluent parser that uses the POSIX#getopt and GNU#getopt_long syntaxes.
      • Text-IO - Aids the creation of full console-based applications.
      • Lanterna - Easy console text-GUI library, similar to curses. (LGPL-3.0-only)
    • Cluster Management

      • Singularity - Mesos framework that makes deployment and operations easy. It supports web services, background workers, scheduled jobs, and one-off tasks.
    • Code Analysis

      • NullAway - Eliminates NullPointerExceptions with low build-time overhead.
      • PMD - Source code analysis for finding bad coding practices.
      • Infer - Modern static analysis tool for verifying the correctness of code.
      • Checkstyle - Static analysis of coding conventions and standards. (LGPL-2.1-or-later)
      • Error Prone - Catches common programming mistakes as compile-time errors.
      • SonarJava - Static analyzer for SonarQube & SonarLint. (LGPL-3.0-only)
      • Spoon - Library for analyzing and transforming Java source code.
      • Spotbugs - Static analysis of bytecode to find potential bugs. (LGPL-2.1-only)
    • Configuration

      • KAConf - Annotation-based configuration system for Java and Kotlin.
      • owner - Reduces boilerplate of properties.
      • owner - Reduces boilerplate of properties.
      • centraldogma - Highly-available version-controlled service configuration repository based on Git, ZooKeeper and HTTP/2.
      • cfg4j - Modern configuration library for distributed apps written in Java.
      • config - Configuration library for JVM languages.
      • dotenv - Twelve-factor configuration library which uses environment-specific files.
    • CSV

      • uniVocity-parsers - One of the fastest and most feature-complete parsers. Also comes with parsers for TSV and fixed-width records.
      • jackson-dataformat-csv - Jackson extension for reading and writing CSV.
      • Super CSV - Powerful CSV parser with support for Dozer, Joda-Time and Java 8.
    • Data Structures

      • Big Queue - Fast and persistent queue based on memory-mapped files.
      • HyperMinHash-java - Probabilistic data structure for computing union, intersection, and set cardinality in loglog space.
      • Persistent Collection - Persistent and immutable analogue of the Java Collections Framework.
      • Protobuf - Google's data interchange format.
      • Tape - Lightning-fast, transactional, file-based FIFO.
      • SBE - Simple Binary Encoding, one of the fastest message formats around.
      • Wire - Clean, lightweight protocol buffers.
    • Database

      • eXist - NoSQL document database and application platform. (LGPL-2.1-only)
      • FlexyPool - Brings metrics and failover strategies to the most common connection pooling solutions.
      • Flyway - Simple database migration tool.
      • HikariCP - High-performance JDBC connection pool.
      • jasync-sql - Async DB driver for MySQL and PostgreSQL.
      • JDBI - Convenient abstraction of JDBC.
      • Jest - Client for the Elasticsearch REST API.
      • Realm - Mobile database to run directly inside phones, tablets or wearables.
      • requery - Modern, lightweight but powerful object mapping and SQL generator. Easily map to or create databases, or perform queries and updates from any Java-using platform.
      • Xodus - Highly concurrent transactional schema-less and ACID-compliant embedded database.
      • Liquibase - Database-independent library for tracking, managing and applying database schema changes.
      • Presto - Distributed SQL query engine for big data.
      • Jedis - Small client for interaction with Redis, with methods for commands.
      • AranoDB - ArangoDB Java driver.
      • Chronicle Map - Efficient, in-memory (opt. persisted to disk), off-heap key-value store.
      • jetcd - Client library for etcd.
      • Jinq - Typesafe database queries via symbolic execution of Java 8 Lambdas (on top of JPA or jOOQ).
      • Leaf - Distributed ID generate service.
      • MariaDB4j - Launcher for MariaDB that requires no installation or external dependencies.
      • Querydsl - Typesafe unified queries.
      • Redisson - Allows for distributed and scalable data structures on top of a Redis server.
      • Speedment - Database access library that utilizes Java 8's Stream API for querying.
    • Dependency Injection

      • Feather - Ultra-lightweight, JSR-330-compliant dependency injection library.
      • Inversion of Control
      • Dagger - Compile-time injection framework without reflection.
      • Governator - Extensions and utilities that enhance Google Guice.
      • Guice - Lightweight and opinionated framework that completes Dagger.
      • HK2 - Lightweight and dynamic dependency injection framework.
      • JayWire - Lightweight dependency injection framework. (LGPL-3.0-only)
    • Distributed Applications

      • JGroups - Toolkit for reliable messaging and cluster creation.
      • Orbit - Virtual actors; adds another level of abstraction to traditional actors.
      • Quasar - Lightweight threads and actors for the JVM.
      • Atomix - Fault-tolerant distributed coordination framework.
      • Failsafe - Simple failure handling with retries and circuit breakers.
      • JGroups - Toolkit for reliable messaging and cluster creation.
      • Dropwizard Circuit Breaker - Circuit breaker design pattern for Dropwizard. (GPL-2.0-only)
      • resilience4j - Functional fault tolerance library.
      • ScaleCube Services - Embeddable Cluster-Membership library based on SWIM and gossip protocol.
      • Zuul - Gateway service that provides dynamic routing, monitoring, resiliency, security, and more.
    • Distributed Transactions

      • Bitronix - Simple but complete implementation of the JTA 1.1 API.
      • Seata - Delivers high performance and easy to use distributed transaction services under a microservices architecture.
    • Distribution

      • Capsule - Simple and powerful packaging and deployment. A fat JAR on steroids, or a "Docker for Java" that supports JVM-optimized containers.
      • packr - Packs JARs, assets and the JVM for native distribution on Windows, Linux and macOS.
      • really-executable-jars-maven-plugin - Maven plugin for making self-executing JARs.
      • IzPack - Setup authoring tool for cross-platform deployments.
      • Boxfuse ![c - Deployment of JVM applications to AWS using the principles of immutable infrastructure.
    • Document Processing

      • zerocell - Annotation-based API for reading data from Excel sheets into POJOs with focus on reduced overhead.
      • documents4j - API for document format conversion using third-party converters such as MS Word.
      • docx4j - Create and manipulate Microsoft Open XML files.
    • Financial

      • Parity - Platform for trading venues.
      • Philadelphia - Low-latency financial information exchange.
      • Square - Integration with the Square API.
      • Stripe - Integration with the Stripe API.
    • Formal Verification

      • CATG - Concolic unit testing engine. Automatically generates unit tests using formal methods.
      • Java Path Finder (JPF) - JVM formal verification tool containing a model checker and more. Created by NASA.
      • OpenJML - Translates JML specifications into SMT-LIB format and passes the proof problems implied by the program to backend solvers. (GPL-2.0-only)
      • Daikon - Detects likely program invariants and generates JML specs based on those invariants.
      • JMLOK 2.0 - Detects inconsistencies between code and JML specification through feedback-directed random tests generation, and suggests a likely cause for each nonconformance detected. (GPL-3.0-only)
      • Checker Framework - Pluggable type systems. Includes nullness types, physical units, immutability types and more. (GPL-2.0-only WITH Classpath-exception-2.0)
    • Functional Programming

      • derive4j - Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching and morphisms. (GPL-3.0-only)
      • Fugue - Functional extensions to Guava.
      • jOOλ - 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.
      • protonpack - Collection of stream utilities.
      • StreamEx - Enhances Java 8 Streams.
      • Functional Java - Implements numerous basic and advanced programming abstractions that assist composition-oriented development.
    • Game Development

      • FXGL - JavaFX Game Development Framework.
      • libGDX - All-round cross-platform, high-level framework.
      • FXGL - JavaFX Game Development Framework.
    • Geospatial

      • Geo - GeoHash utilities in Java.
      • Geotoolkit.org - Library for developing geospatial applications. Built on top of the Apache SIS project. (LGPL-2.1-only)
      • GraphHopper - Road-routing engine. Used as a Java library or standalone web service.
      • H2GIS - Spatial extension of the H2 database. (LGPL-3.0-only)
      • Jgeohash - Library for using the GeoHash algorithm.
      • Mapsforge - Map rendering based on OpenStreetMap data. (LGPL-3.0-only)
      • Spatial4j - General-purpose spatial/geospatial library.
      • H2GIS - Spatial extension of the H2 database. (LGPL-3.0-only)
    • High Performance

      • Disruptor - Inter-thread messaging library.
      • JCTools - Concurrency tools currently missing from the JDK.
      • HPPC - Primitive collections.
      • Koloboke - Hash sets and hash maps.
      • Eclipse Collections - Collections framework inspired by Smalltalk.
      • Disruptor - Inter-thread messaging library.
      • fastutil - Fast and compact type-specific collections.
    • Hypermedia Types

      • Siren4J - Library for the Siren specification.
      • JSON-LD - JSON-LD implementation.
    • HTTP Clients

      • Async Http Client - Asynchronous HTTP and WebSocket client library.
      • Feign - HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.
      • Play WS - Typesafe client with reactive streams and caching.
      • Ribbon - Client-side IPC library that is battle-tested in cloud.
      • Riptide - Client-side response routing for Spring's RestTemplate.
      • unirest-java - Simplified, lightweight HTTP client library.
      • Feign - HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.
      • restQL-core-java - Microservice query language that fetches information from multiple services.
      • OkHttp - HTTP and SPDY client.
      • Retrofit - Typesafe REST client.
    • Imagery

      • Tess4J - JNA wrapper for Tesseract OCR API.
      • Thumbnailator - High-quality thumbnail generation library.
      • TwelveMonkeys - Collection of plugins that extend the number of supported image file formats.
      • image-comparison - Compares two images with the same sizes and shows the differences visually by drawing rectangles.
      • ZXing - Multi-format 1D/2D barcode image processing library.
      • Imgscalr - Simple, efficient and hardware-accelerated image-scaling library implemented in pure Java 2D.
    • Introspection

      • ClassGraph - ClassGraph (formerly FastClasspathScanner) is an uber-fast, ultra-lightweight, parallelized classpath scanner and module scanner for Java, Scala, Kotlin and other JVM languages.
      • Mirror - Mirror was created to bring light to a simple problem, usually named ReflectionUtil, which is on almost all projects that rely on reflection to do advanced tasks.
      • ReflectASM - ReflectASM is a very small Java library that provides high performance reflection by using code generation.
      • Reflections - 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.
      • jOOR - jOOR stands for jOOR Object Oriented Reflection. It is a simple wrapper for the java.lang.reflect package.
    • Job Scheduling

      • Quartz - Feature-rich, open source job scheduling library that can be integrated within virtually any Java application.
      • Sundial - Lightweight framework to simply define jobs, define triggers and start the scheduler.
      • Wisp - Simple library with minimal footprint and straightforward API.
      • db-scheduler - Persistent and cluster-friendly scheduler.
    • JSON

      • DSL-JSON - JSON library with advanced compile time databinding.
      • HikariJSON - High-performance JSON parser, 2x faster than Jackson.
      • jackson-modules-java8 - Set of Jackson modules for Java 8 datatypes and features.
      • jsoniter - Fast and flexible library with iterator and lazy parsing API.
      • Yasson - Binding layer between classes and JSON documents similar to JAXB.
      • JsonSurfer - Streaming JsonPath processor dedicated to processing big and complicated JSON data.
      • Gson - Serializes objects to JSON and vice versa. Good performance with on-the-fly usage.
      • Jackson - Similar to GSON, but offers performance gains if you need to instantiate the library more often.
      • Moshi - Modern JSON library, less opinionated and uses built-in types like List and Map.
      • Genson - Powerful and easy-to-use Java-to-JSON conversion library.
      • JsonSurfer - Streaming JsonPath processor dedicated to processing big and complicated JSON data.
      • JsonPath - Extract data from JSON using XPATH-like syntax.
      • Jackson-datatype-money - Open-source Jackson module to support JSON serialization and deserialization of JavaMoney data types.
      • JSON-io - Convert Java to JSON. Convert JSON to Java. Pretty print JSON. Java JSON serializer.
      • LoganSquare - JSON parsing and serializing library based on Jackson's streaming API. Outperforms GSON & Jackson's library.
      • fastjson - Very fast processor with no additional dependencies and full data binding.
      • Jolt - JSON to JSON transformation tool.
    • JVM and JDK

      • OpenJ9 - 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.
      • SAP Machine - SAP's no-cost, rigorously tested and JCK-verified OpenJDK friendly fork. (GPL-2.0-only WITH Classpath-exception-2.0)
      • Liberica JDK - Built from OpenJDK, thoroughly tested and passed the JCK. (GPL-2.0-only WITH Classpath-exception-2.0)
      • Open JDK - Open JDK community home. (GPL-2.0-only WITH Classpath-exception-2.0)
      • OpenJ9 - 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.
      • Zulu - OpenJDK builds for Windows, Linux, and macOS. (GPL-2.0-only WITH Classpath-exception-2.0)
      • Avian - JVM with JIT, AOT modes and iOS port.
      • Graal - Polyglot embeddable JVM. (GPL-2.0-only WITH Classpath-exception-2.0)
      • ParparVM - VM with non-blocking, concurrent GC for iOS. (GPL-2.0-only WITH Classpath-exception-2.0)
      • RedHat Open JDK - RedHat's OpenJDK distribution. (GPL-2.0-only WITH Classpath-exception-2.0)
    • Logging

      • Logbook - Extensible, open-source library for HTTP request and response logging.
      • Tracer - Call tracing and log correlation in distributed systems.
      • Apache Log4j 2 - Complete rewrite with a powerful plugin and configuration architecture.
      • Logback - Robust logging library with interesting configuration options via Groovy.
      • Kibana - Analyzes and visualizes log files. Some features require payment.
      • Logstash - Tool for managing log files.
      • p6spy - Enables logging for all JDBC transactions without changes to the code.
      • Tracer - Call tracing and log correlation in distributed systems.
    • Machine Learning

      • DatumBox - Provides several algorithms and pre-trained models for natural language processing.
      • DeepDive - Creates structured information from unstructured data and integrates it into an existing database.
      • Synapses - Lightweight library for neural networks.
      • DeepDive - Creates structured information from unstructured data and integrates it into an existing database.
      • Weka - Collection of algorithms for data mining tasks ranging from pre-processing to visualization. (GPL-3.0-only)
      • JSAT - Algorithms for pre-processing, classification, regression, and clustering with support for multi-threaded execution. (GPL-3.0-only)
      • Oryx 2 - Framework for building real-time, large-scale machine learning applications. Includes end-to-end applications for collaborative filtering, classification, regression, and clustering.
      • Smile - Statistical Machine Intelligence and Learning Engine provides a set of machine learning algorithms and a visualization library.
    • Messaging

      • NATS client - NATS client.
      • Aeron - Efficient, reliable, unicast and multicast message transport.
      • EventBus - Simple publish/subscribe event bus.
      • JeroMQ - Implementation of ZeroMQ.
      • Nakadi - Provides a RESTful API on top of Kafka.
      • RabbitMQ Java client - RabbitMQ client.
      • Smack - Cross-platform XMPP client library.
    • Microservice

      • Apollo - Libraries for writing composable microservices.
      • Micronaut - Modern full-stack framework with focus on modularity, minimal memory footprint and startup time.
      • Armeria - Asynchronous RPC/REST client/server library built on top of Java 8, Netty, HTTP/2, Thrift and gRPC.
      • consul-api - Client for the Consul API: a distributed, highly available and datacenter-aware registry/discovery service.
      • Eureka - REST-based service registry for resilient load balancing and failover.
    • Miscellaneous

      • FF4J - Feature Flags for Java.
      • FizzBuzz Enterprise Edition - No-nonsense implementation of FizzBuzz made by serious businessmen for serious business purposes. (No explicit license)
      • J2ObjC - Java-to-Objective-C translator for porting Android libraries to iOS.
      • JavaCV - Java interface to OpenCV, FFmpeg, and more.
      • JBot - Framework for building chatbots. (GPL-3.0-only)
      • JCuda - JCuda offers Java bindings for CUDA and CUDA-related libraries.
      • Jimfs - In-memory file system.
      • Maven Wrapper - Analogue of Gradle Wrapper for Maven, allows building projects without installing maven.
      • Membrane Service Proxy - Open-source, reverse-proxy framework.
      • MinimalFTP - Lightweight, small and customizable FTP server.
      • Modernizer - Detect uses of legacy Java APIs.
      • PipelinR - Small utility library for using handlers and commands with pipelines.
      • Polyglot for Maven - Extensions for Maven 3.3.1+ that allows writing the POM model in dialects other than XML.
      • Simple Java Mail - Mailing with a clean and fluent API.
      • Smooks - Extensible framework for building applications that process data which means bindings, transformations, message processing and enrichment. (LGPL-3.0-only)
      • TypeTools - Tools for resolving generic types.
      • XMLBeam - Processes XML by using annotations or XPath within code.
      • yGuard - Obfuscation via renaming and shrinking.
      • JavaX - Reinventing and extending Java with a focus on simplicity. (No explicit license)
      • Membrane Service Proxy - Open-source, reverse-proxy framework.
      • JBake - Static website generator.
      • JavaX - Reinventing and extending Java with a focus on simplicity. (No explicit license)
      • JCuda - JCuda offers Java bindings for CUDA and CUDA-related libraries.
      • JPad - Snippet runner.
      • OctoLinker - Browser extension which allows to navigate through code on GitHub more efficiently.
      • CQEngine - Ultra-fast, SQL-like queries on Java collections.
      • Design Patterns - Implementation and explanation of the most common design patterns.
      • Modern Java - A Guide to Java 8 - Popular Java 8 guide.
      • JPad - Snippet runner.
      • Modernizer - Detect uses of legacy Java APIs.
    • Monitoring

      • Automon - Combines the power of AOP with monitoring and/or logging tools.
      • Failsafe Actuator - Out of the box monitoring of Failsafe Circuit Breaker in Spring-Boot environment.
      • LeakCanary - Memory leak detection.
      • Failsafe Actuator - Out of the box monitoring of Failsafe Circuit Breaker in Spring-Boot environment.
      • JavaMelody - Performance monitoring and profiling.
      • Jaeger client - Jaeger client.
      • jmxtrans - 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.
      • nudge4j - Remote developer console from the browser for Java 8 via bytecode injection.
      • SPM ![c - Performance monitor with distributing transaction tracing for JVM apps.
      • Stagemonitor - Open-source performance monitoring and transaction tracing for JVM apps.
      • Sysmon - Lightweight platform monitoring tool for Java VMs.
      • Pinpoint - Open-source APM tool.
    • PDF

      • Dynamic Jasper - Abstraction layer to JasperReports. (LGPL-3.0-only)
      • DynamicReports - Simplifies JasperReports. (LGPL-3.0-only)
      • flyingsaucer - XML/XHTML and CSS 2.1 renderer. (LGPL-2.1-or-later)
      • JasperReports - Complex reporting engine. (LGPL-3.0-only)
      • Open HTML to PDF - Properly supports modern PDF standards based on flyingsaucer and Apache PDFBox.
      • OpenPDF - Open-source iText fork. (LGPL-3.0-only & MPL-2.0)
      • iText ![c - Creates PDF files programmatically.
    • Code Coverage

      • Clover - Relies on source-code instrumentation instead of bytecode instrumentation.
      • JaCoCo - Framework that enables collection of code coverage metrics, using both offline and runtime bytecode instrumentation.
      • Cobertura - Relies on offline (or static) bytecode instrumentation and class loading to collect code coverage metrics. (GPL-2.0-only)
    • Code Generators

      • Joda-Beans - Small framework that adds queryable properties to Java, enhancing JavaBeans.
      • ADT4J - JSR-269 code generator for algebraic data types.
      • Auto - Generates factory, service, and value classes.
      • FreeBuilder - Automatically generates the Builder pattern.
      • JavaPoet - API to generate source files.
      • JHipster - Yeoman source code generator for Spring Boot and AngularJS.
    • GUI

      • JavaFX - Successor of Swing.
      • Scene Builder - Visual layout tool for JavaFX applications.
      • SWT - Graphical widget toolkit.
    • IDE

      • Visual Studio Code - Provides Java support for lightweight projects with a simple, modern workflow by using extensions from the internal marketplace.
    • ORM

      • Doma 2 - 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.
      • Ebean - Provides simple and fast data access.
      • Hibernate - Robust and widely used, with an active community. (LGPL-2.1-only)
      • Doma 2 - 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.
      • SimpleFlatMapper - Simple database and CSV mapper.
    • Platform

      • Logging - Wrapper around a variety of logging API implementations.
      • Math - Lightweight, self-contained mathematics and statistics components.
      • Spring - Provides many packages for dependency injection, aspect-oriented programming, security, etc.
      • Orienteer - Open-source business application platform for rapid configuration/development of CRM, ERP, LMS and other applications.
    • Science

      • Morpheus - 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.
      • DataMelt - Environment for scientific computation, data analysis and data visualization. (GPL-3.0-or-later)
      • JFreeChart - 2D chart library for Swing, JavaFX and server-side applications. (LGPL-2.1-only)
      • Morpheus - 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.
      • Tablesaw - Includes a data-frame, an embedded column store, and hundreds of methods to transform, summarize, or filter data.
      • Erdos - Modular, light and easy graph framework for theoretic algorithms.
      • JGraphT - Graph library that provides mathematical graph-theory objects and algorithms.
      • JGraphX - Library for visualizing (mainly Swing) and interacting with node-edge graphs.
      • Mines Java Toolkit - Library for geophysical scientific computation, visualization and digital signal analysis.
      • Orson-Charts - 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)
      • XChart - Light-weight library for plotting data. Many customizable chart types are available.
    • Security

      • Bouncy Castle - All-purpose cryptographic library and JCA provider offering a wide range of functions, from basic helpers to PGP/SMIME operations.
      • Themis - 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.
      • Bouncy Castle - All-purpose cryptographic library and JCA provider offering a wide range of functions, from basic helpers to PGP/SMIME operations.
      • Hdiv - 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.
      • jjwt - JSON web token for Java and Android.
      • Jwks RSA - JSON Web Key Set parser.
      • Kalium - Binding for the Networking and Cryptography (NaCl) library.
      • Keywhiz - System for distributing and managing secrets.
      • Nbvcxz - Advanced password strength estimation.
      • OACC - Provides permission-based authorization services.
      • pac4j - Security engine.
      • SecurityBuilder - Fluent Builder API for JCA and JSSE classes and especially X.509 certificates.
      • Tink - Provides a simple and misuse-proof API for common cryptographic tasks.
      • Vault - Secures, stores, and tightly controls access to tokens, passwords, certificates, API keys, and other secrets. It handles leasing, key revocation, key rolling, and auditing. Through a unified API, users can access an encrypted Key/Value store and network encryption-as-a-service, or generate AWS IAM/STS credentials, SQL/NoSQL databases, X.509 certificates, SSH credentials, and more.
      • Keycloak - Integrated SSO and IDM for browser apps and RESTful web services.
    • Testing

      • GreenMail - In-memory email server for integration testing. Supports SMTP, POP3 and IMAP including SSL. (GPL-2.0-only)
      • Pact JVM - Consumer-driven contract testing.
      • Awaitility - DSL for synchronizing asynchronous operations.
      • REST Assured - DSL for easy testing of REST/HTTP services.
      • JBehave - Extensively configurable framework that describes stories.
      • JUnit - Common testing framework.
      • AssertJ - Fluent assertions that improve readability.
      • Hamcrest - Matchers that can be combined to create flexible expressions of intent.
      • pojo-tester - Automatically performs tests on basic POJO methods. (LGPL-3.0-only)
      • PowerMock - Mocks static methods, constructors, final classes and methods, private methods, and removal of static initializers.
      • WireMock - Stubs and mocks web services.
      • ConcurrentUnit - Toolkit for testing multi-threaded and asynchronous applications.
      • Hoverfly Java - Native bindings for Hoverfly, a proxy which allows you to simulate HTTP services.
      • Karate - DSL that combine API test-automation, mocks and performance-testing making testing REST/HTTP services easy.
      • Cucumber - Provides a way to describe features in a plain language which customers can understand.
      • J8Spec - Follows a Jasmine-like syntax.
      • Lamdba Behave - Aims to provide a fluent API to write tests in long and descriptive sentences that read like plain English.
      • Beanmother - Sets up beans from YAML fixtures.
      • Fixture Factory - Generates fake objects from a template.
      • jFairy - Fake data generator.
      • Randomized Testing - JUnit test runner and plugins for running JUnit tests with pseudo-randomness.
      • Java Faker - Port of Ruby's fake data generator.
      • ArchUnit - Test library for specifying and asserting architecture rules.
      • XMLUnit - Simplifies testing for XML output.
      • junit-dataprovider - TestNG-like data provider/runner for JUnit.
      • Mutability Detector - Reports whether instances of a given class are immutable.
      • raml-tester - Tests if a request/response matches a given RAML definition.
      • TestContainers - Provides throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.
      • JMockit - Integration testing, API mocking and faking, and code coverage.
      • Mockito - Mocking framework that lets you write tests with a clean and simple API.
      • Moco - Concise web services for stubs and mocks.
      • Serenity BDD - Automated Acceptance testing and reporting library that works with Cucumber, JBehave and JUnit to make it easier to write high quality executable specifications.
    • Utility

      • Guava - Collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and more.
      • cactoos - Collection of object-oriented primitives.
      • bucket4j - Rate limiting library based on token-bucket algorithm.
      • CRaSH - Provides a shell into a JVM that's running CRaSH. Used by Spring Boot and others. (LGPL-2.1-or-later)
      • Dex - Java/JavaFX tool capable of powerful ETL and data visualization.
      • fswatch - Micro library to watch for directory file system changes, simplifying java.nio.file.WatchService.
      • Gephi - Cross-platform for visualizing and manipulating large graph networks. (GPL-3.0-only)
      • JavaVerbalExpressions - Library that helps with constructing difficult regular expressions.
      • JGit - Lightweight, pure Java library implementing the Git version control system.
      • minio-java - Provides simple APIs to access any Amazon S3-compatible object storage server.
      • Underscore-java - Port of Underscore.js functions.
      • JADE - Framework and environment for building and debugging multi-agent systems. (LGPL-2.0-only)
    • Web Frameworks

      • Vaadin Flow - Event-driven framework that uses standard web components. Server-side architecture with Ajax on the client side.
      • Grails - Groovy framework that provides a highly productive environment by favoring convention over configuration, no XML and support for mixins.
      • Ninja - Full-stack web framework.
      • Play - Built on Akka, it provides predictable and minimal resource consumption (CPU, memory, threads) for highly-scalable applications in Java and Scala.
      • Firefly - Asynchronous framework for rapid development of high-performance web application.
      • Pippo - Small, highly modularized, Sinatra-like framework.
      • Takes - Opinionated web framework which is built around the concepts of True Object-Oriented Programming and immutability.
      • PrimeFaces - JSF framework with both free and commercial/support versions and frontend components.
      • Bootique - Minimally opinionated framework for runnable apps.
    • REST Frameworks

      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • RESTEasy - Fully certified and portable implementation of the JAX-RS specification.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • Dropwizard - Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.
      • Elide - Opinionated framework for JSON- or GraphQL-APIs based on a JPA data model.
      • javalin - Javalin is just a few thousand lines of code on top of Jetty, which means its performance is almost equivalent to pure Jetty.
      • RESTEasy - Fully certified and portable implementation of the JAX-RS specification.
      • Dropwizard - Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.
      • Microserver - A 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.
      • rest.li - 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.
      • RestExpress - Thin wrapper on the JBoss Netty HTTP stack that provides scaling and performance.
      • Restlet Framework - Pioneering framework with powerful routing and filtering capabilities, and a unified client and server API.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
      • springdoc-openapi - Automates the generation of API documentation using Spring Boot projects.
      • Crnk - Implementation of the JSON API specification to build resource-oriented REST endpoints with sorting, filtering, paging, linking, object graphs, type-safety, bulk updates, integrations and more.
    • Template Engine

      • Jtwig - Modular, configurable and fully tested template engine.
      • Handlebars.java - Logicless and semantic Mustache templates.
      • Jtwig - Modular, configurable and fully tested template engine.
      • Thymeleaf - Aims to be a substitute for JSP and works for XML files.
      • Jade4J - Implementation of Pug (formerly known as Jade).
      • Rocker - Optimized, memory efficient and speedy template engine producing statically typed, plain objects.
    • Networking

      • Nifty - Implementation of Thrift clients and servers on Netty.
      • AkkaGRPC - Support for building streaming gRPC servers and clients on top of Akka Streams.
      • Comsat - Integrates standard Java web-related APIs with Quasar fibers and actors.
      • Dubbo - High-performance RPC framework.
      • Finagle - Extensible RPC system for constructing high-concurrency servers. It implements uniform client and server APIs for several protocols, and is protocol-agnostic to simplify implementation of new protocols.
      • gRPC - RPC framework based on protobuf and HTTP/2.
      • KryoNet - Provides a clean and simple API for efficient TCP and UDP client/server network communication using NIO and Kryo.
      • Nifty - Implementation of Thrift clients and servers on Netty.
      • ServiceTalk - Framework built on Netty with APIs tailored to specific protocols and support for multiple programming paradigms.
      • sshj - Programatically use SSH, SCP or SFTP.
      • TLS Channel - Implements a ByteChannel interface over SSLEngine, enabling easy-to-use (socket-like) TLS.
      • urnlib - Represent, parse and encode URNs, as in RFC 2141. (GPL-3.0-only)
      • Apache Solr - Enterprise search engine optimized for high-volume traffic.
      • Indexer4j - Simple and light full text indexing and searching library.
      • Elasticsearch - Distributed, multitenant-capable, full-text search engine with a RESTful web interface and schema-free JSON documents.
    • Server

      • Jetty - Provides a Web server and javax.servlet container, plus support for HTTP/2, WebSocket, OSGi, JMX, JNDI, JAAS and many other integrations.
      • WildFly - Formerly known as JBoss and developed by Red Hat with extensive Java EE support. (LGPL-2.1-only)
      • nanohttpd - Tiny, easily embeddable HTTP server.
    • Version Managers

      • jenv - Java Version Manager inspired by rbenv. Can configure globally or per project. Tested on Debian and macOS.
      • jabba - Java Version Manager inspired by nvm. Supports macOS, Linux and Windows.
      • SDKMan - Java Version Manager inspired by RVM and rbenv. Supports UNIX-based platforms and Windows.
    • Web Crawling

      • jsoup - Scrapes, parses, manipulates and cleans HTML.
      • Crawler4j - Simple and lightweight web crawler.
      • StormCrawler - SDK for building low-latency and scalable web crawlers.
      • webmagic - Scalable crawler with downloading, url management, content extraction and persistent.
      • StormCrawler - SDK for building low-latency and scalable web crawlers.
    • Development

      • NoException - Allows checked exceptions in functional interfaces and converts exceptions to Optional return.
      • Faux Pas - 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.
      • HotswapAgent - Unlimited runtime class and resource redefinition. (GPL-2.0-only)
      • JavaParser - Parse, modify and generate Java code.
      • JavaSymbolSolver - Symbol solver.
      • Manifold - Re-energizes Java with powerful features like type-safe metaprogramming, structural typing and extension methods.
      • SneakyThrow - Ignores checked exceptions without bytecode manipulation. Can also be used inside Java 8 stream operations.
    • Native

      • JavaCPP - Provides efficient and easy access to native C++.
      • JNA - Work with native libraries without writing JNI. Also provides interfaces to common system libraries.
      • JNR - 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](http://openjdk.java.net/projects/panama).
    • Natural Language Processing

      • Beagle - Stored full-text search query engine.
      • CogCompNLP - Provides common annotators for plain text input. (Research and Academic Use License)
      • Lingua - Natural language detection library, especially suited for short paragraphs of text.
      • LingPipe - Toolkit for tasks ranging from POS tagging to sentiment analysis.
      • CoreNLP - Provides a set of fundamental tools for tasks like tagging, named entity recognition, and sentiment analysis. (GPL-3.0-or-later)
    • PaaS

    • Performance analysis

      • honest-profiler - Low-overhead, bias-free sampling profiler.
      • jHiccup - Logs and records platform JVM stalls.
      • JITWatch - Analyze the JIT compiler optimisations made by the HotSpot JVM.
      • LatencyUtils - Utilities for latency measurement and reporting.
      • JMH - Harness for building, running, and analysing nano/micro/milli/macro benchmarks written in Java and other languages targeting the JVM. (GPL-2.0 only WITH Classpath-exception-2.0)
    • Processes

      • ch.vorburger.exec - Convenient API around Apache Commons Exec.
      • zt-exec - Provides a unified API to Apache Commons Exec and ProcessBuilder.
      • zt-process-killer - Stops processes started from Java or the system processes via PID.
    • Reactive libraries

      • Akka - Toolkit and runtime for building concurrent, distributed, fault-tolerant and event-driven applications.
      • Reactive Streams - Provides a standard for asynchronous stream processing with non-blocking backpressure.
      • RxJava - Allows for composing asynchronous and event-based programs using observable sequences.
    • Serialization

      • FlatBuffers - Memory-efficient serialization library that can access serialized data without unpacking and parsing it.
      • FST - JDK-compatible, high-performance object graph serialization.
      • Kryo - Fast and efficient object graph serialization framework.
      • MessagePack - Efficient binary serialization format.
      • PHP Serializer - Serializing objects in the PHP serialization format.
    • Compiler-compiler

      • JavaCC - Parser generator that generates top-down parsers. Allows lexical state switching and permits extended BNF specifications.
    • Constraint Satisfaction Problem Solver

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

      • iCal4j - Parse and build iCalendar [RFC 5545](https://tools.ietf.org/html/rfc5545) data models.
      • ThreeTen-Extra - Additional date-time classes that complement those in JDK 8.
      • Time4J - Advanced date and time library. (LGPL-2.1-only)
  • Resources

  • Contributing