awesome-java/README.md

# Awesome Java [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38d29fed78fa85652e3a63e154dd8e8829/media/badge.svg)](https://github.com/sindresorhus/awesome)

A curated list of awesome Java frameworks, libraries and software.

- [Awesome Java](#awesome-java)
    - [Ancients](#ancients)
    - [Bean Mapping](#bean-mapping)
    - [Build](#build)
    - [Bytecode Manipulation](#bytecode-manipulation)
    - [Caching](#caching)
    - [Cluster Management](#cluster-management)
    - [Code Analysis](#code-analysis)
    - [Code Coverage](#code-coverage)
    - [Code Generators](#code-generators)
    - [Command-line Argument Parsers](#command-line-argument-parsers)
    - [Compiler-compiler](#compiler-compiler)
    - [Configuration](#configuration)
    - [Constraint Satisfaction Problem Solver](#constraint-satisfaction-problem-solver)
    - [CSV](#csv)
    - [Data structures](#data-structures)
    - [Database](#database)
    - [Date and Time](#date-and-time)
    - [Dependency Injection](#dependency-injection)
    - [Development](#development)
    - [Distributed Applications](#distributed-applications)
    - [Distributed Transactions](#distributed-transactions)
    - [Distribution](#distribution)
    - [Document Processing](#document-processing)
    - [Formal Verification](#formal-verification)
    - [Functional Programming](#functional-programming)
    - [Game Development](#game-development)
    - [Geospatial](#geospatial)
    - [GUI](#gui)
    - [High Performance](#high-performance)
    - [HTTP Clients](#http-clients)
    - [Hypermedia Types](#hypermedia-types)
    - [IDE](#ide)
    - [Imagery](#imagery)
    - [JSON Processing](#json-processing)
    - [JSON](#json)
    - [JVM and JDK](#jvm-and-jdk)
    - [Logging](#logging)
    - [Machine Learning](#machine-learning)
    - [Messaging](#messaging)
    - [Microservice](#microservice)
    - [Miscellaneous](#miscellaneous)
    - [Monitoring](#monitoring)
    - [Native](#native)
    - [Natural Language Processing](#natural-language-processing)
    - [Networking](#networking)
    - [ORM](#orm)
    - [PaaS](#paas)
    - [PDF](#pdf)
    - [Performance analysis](#performance-analysis)
    - [Platform](#platform)
    - [Reactive libraries](#reactive-libraries)
    - [REST Frameworks](#rest-frameworks)
    - [Science](#science)
    - [Search](#search)
    - [Security](#security)
    - [Serialization](#serialization)
    - [Server](#server)
    - [Template Engine](#template-engine)
    - [Testing](#testing)
    - [Utility](#utility)
    - [Version Managers](#version-managers)
    - [Web Crawling](#web-crawling)
    - [Web Frameworks](#web-frameworks)
- [Resources](#resources)
    - [Awesome Lists](#awesome-lists)
    - [Communities](#communities)
    - [Frontends](#frontends)
    - [Influential Books](#influential-books)
    - [Podcasts and Screencasts](#podcasts-and-screencasts)
    - [Twitter](#twitter)
    - [Websites](#websites)
- [Contributing](#contributing)

## Ancients

*In existence since the beginning of time, and which people will continue using long after the hype has waned.*

* [Apache Ant](https://ant.apache.org/) - Build process management with XML.
* [Apache Hadoop](https://hadoop.apache.org/) - Storage and large-scale processing of data sets on clusters of commodity hardware.
* [Apache OpenNLP](https://opennlp.apache.org/) - Toolkit for common tasks like tokenization.
* [Apache Velocity](https://velocity.apache.org/) - A template engine for HTML pages, emails or source code generation.
* [FreeMarker](http://freemarker.org/) - General templating engine with no heavyweight or opinionated dependencies.
* [GlassFish](https://javaee.github.io/glassfish/) - Application server and reference implementation for Java EE, sponsored by Oracle.
* [GWT](http://www.gwtproject.org/) - Toolbox that includes a Java-to-JavaScript compiler for client-side code, XML parser, API for RPC, JUnit integration, internationalization support and widgets for the GUI.
* [HornetQ](https://hornetq.jboss.org/) - Clear, concise, modular and made for embedding.
* [Java Modeling Language (JML)](http://www.eecs.ucf.edu/~leavens/JML/) - Behavioral interface specification language useful for specifying the behavior of code modules. It combines Eiffel's Design by Contract approach with the model-based specification approach of the Larch family of interface specification languages, with some elements of the refinement calculus. Used by several other verification tools.
* [JavaCC](https://javacc.org/) - Parser generator with syntactic lookahead.
* [JavaServer Faces](https://javaee.github.io/javaserverfaces-spec/) - Oracle's open-source implementation of the JSF standard, Mojarra.
* [JavaServer Pages](https://javaee.github.io/javaee-jsp-api/) - Common templating for websites with custom tag libraries.
* [Launch4j](http://launch4j.sourceforge.net/) - Wraps JARs in lightweight and native Windows executables.
* [Quartz](https://github.com/quartz-scheduler/quartz) - Open-source job scheduler library with Apache 2.0 license.
* [RxJava](https://github.com/ReactiveX/RxJava) - Library for composing asynchronous and event-based programs using observable sequences from the JVM.
* [Trove](http://trove.starlight-systems.com/) - High-performance primitive collections.

## Bean Mapping

*Frameworks that ease bean mapping.*

* [Dozer](https://github.com/DozerMapper/dozer/) - Mapper that copies data from one object to another using annotations and API or XML configuration.
* [JMapper](https://jmapper-framework.github.io/jmapper-core/) - Uses byte code manipulation for lightning-fast mapping. Supports annotations and API or XML configuration.
* [MapStruct](https://github.com/mapstruct/mapstruct) - Code generator that simplifies mappings between different bean types, based on a convention-over-configuration approach.
* [ModelMapper](https://github.com/jhalterman/modelmapper) - Intelligent object mapping library that automatically maps objects to each other.
* [Orika](https://github.com/orika-mapper/orika) - JavaBean-mapping framework that recursively copies (among other capabilities) data from one object to another.
* [Selma](https://github.com/xebia-france/selma) - Annotation processor-based bean mapper.

## Build

*Tools that handle the build cycle and dependencies of an application.*

* [Apache Maven](https://maven.apache.org/) - Declarative build and dependency management that favors convention over configuration. It might be preferable to Apache Ant, which uses a rather procedural approach and can be difficult to maintain.
* [Bazel](https://bazel.io) - Tool from Google that builds code quickly and reliably.
* [Gradle](https://gradle.org/) - Incremental builds programmed via Groovy instead of declaring XML. Works well with Maven's dependency management.

## Bytecode Manipulation

*Libraries to manipulate bytecode programmatically.*

* [ASM](https://asm.ow2.org/) - All-purpose, low-level bytecode manipulation and analysis.
* [Byte Buddy](http://bytebuddy.net/) - Further simplifies bytecode generation with a fluent API.
* [Byteman](https://byteman.jboss.org/) - Manipulate bytecode at runtime via DSL (rules); mainly for testing/troubleshooting.
* [cglib](https://github.com/cglib/cglib) - Bytecode generation library.
* [Javassist](https://jboss-javassist.github.io/javassist/) - Tries to simplify bytecode editing.

## Caching

*Libraries that provide caching facilities.*

* [Caffeine](https://github.com/ben-manes/caffeine) - High-performance, near-optimal caching library.
* [Ehcache](http://www.ehcache.org/) - Distributed general-purpose cache.
* [Infinispan](http://infinispan.org/) - Highly concurrent key/value datastore used for caching.

## Cluster Management

*Frameworks that can dynamically manage applications inside of a cluster.*

* [Apache Aurora](https://aurora.apache.org/) - Mesos framework for long-running services and cron jobs.
* [Apache Mesos](https://mesos.apache.org/) - Abstracts CPU, memory, storage, and other compute resources away from machines.
* [Singularity](http://getsingularity.com/) - Mesos framework that makes deployment and operations easy. It supports web services, background workers, scheduled jobs, and one-off tasks.

## Code Analysis

*Tools that provide metrics and quality measurements.*

* [Checkstyle](https://github.com/checkstyle/checkstyle) - Static analysis of coding conventions and standards.
* [Error Prone](https://github.com/google/error-prone) - Catches common programming mistakes as compile-time errors.
* [Spotbugs](https://github.com/spotbugs/spotbugs) - Static analysis of bytecode to find potential bugs.
* [Infer](https://github.com/facebook/infer) - Modern static analysis tool for verifying the correctness of code.
* [jQAssistant](https://jqassistant.org/) - Static code analysis with Neo4J-based query language.
* [PMD](https://github.com/pmd/pmd) - Source code analysis for finding bad coding practices.
* [Sourcetrail ![c]](https://www.sourcetrail.com) - Visual source code navigator.
* [Spoon](https://github.com/INRIA/spoon/) - Library for analyzing and transforming Java source code.

## Code Coverage

*Frameworks and tools that enable code coverage metrics collection for test suites.*

* [Clover ![c]](https://www.atlassian.com/software/clover/overview) - Relies on source-code instrumentation instead of bytecode instrumentation.
* [Cobertura](https://cobertura.github.io/cobertura/) - Relies on offline (or static) bytecode instrumentation and class loading to collect code coverage metrics.
* [JaCoCo](http://eclemma.org/jacoco/) - Framework that enables collection of code coverage metrics, using both offline and runtime bytecode instrumentation.

## Code Generators

*Tools that generate patterns for repetitive code in order to reduce verbosity and error-proneness.*

* [ADT4J](https://github.com/sviperll/adt4j) - JSR-269 code generator for algebraic data types.
* [Auto](https://github.com/google/auto) - Generates factory, service, and value classes.
* [FreeBuilder](https://github.com/google/FreeBuilder) - Automatically generates the Builder pattern.
* [Immutables](https://immutables.github.io/) - Annotation processors to generate simple, safe and consistent value objects.
* [JavaPoet](https://github.com/square/javapoet) - API to generate source files.
* [JHipster](https://github.com/jhipster/generator-jhipster) - Yeoman source code generator for Spring Boot and AngularJS.
* [Joda-Beans](http://www.joda.org/joda-beans/) - Small framework that adds queryable properties to Java, enhancing JavaBeans.
* [Lombok](https://projectlombok.org/) - Code generator that aims to reduce verbosity.

## Command-line Argument Parsers

*Libraries that make it easy to parse command line options, arguments, etc.*

* [Airline](https://github.com/airlift/airline) - Annotation-based framework for parsing Git-like command-line arguments.
* [args4j](http://args4j.kohsuke.org/) - Small library to parse command-line arguments.
* [JCommander](http://jcommander.org/) - Command-line argument-parsing framework with custom types and validation via implementing interfaces.
* [JOpt Simple](https://pholser.github.io/jopt-simple/) - Simple parser that uses the POSIX getopt() and GNU getopt_long() syntaxes. Uses a fluent API instead of annotations.
* [picocli](http://picocli.info/) - ANSI colors and styles in usage help. Can be included as source to avoid dependency. Annotation-based, POSIX/GNU/any syntax, subcommands, strong typing for both options and positional args.

## Compiler-compiler

*Frameworks that help to create parsers, interpreters or compilers.*

* [ANTLR](http://www.antlr.org/) - Complex full-featured framework for top-down parsing.
* [JFlex](http://jflex.de/) - A lexical analyzer generator.

## Configuration

*Libraries that provide external configuration.*

* [centraldogma](https://github.com/line/centraldogma) - Highly-available version-controlled service configuration repository based on Git, ZooKeeper and HTTP/2.
* [cfg4j](https://github.com/cfg4j/cfg4j) - Modern configuration library for distributed apps written in Java.
* [config](https://github.com/typesafehub/config) - Configuration library for JVM languages.
* [dotenv](https://github.com/shyiko/dotenv) - A twelve-factor configuration library for Java.
* [ini4j](http://ini4j.sourceforge.net/) - Provides an API for handling Windows' INI files.
* [KAConf](https://github.com/mariomac/kaconf) - Annotation-based configuration system for Java and Kotlin.
* [owner](https://github.com/lviggiano/owner) - Reduces boilerplate of properties.

## Constraint Satisfaction Problem Solver

*Libraries that help with implementing optimization and satisfiability problems.*

* [Choco](http://choco-solver.org/) - Off-the-shelf constraint satisfaction problem solver that uses constraint programming techniques.
* [JaCoP](https://github.com/radsz/jacop/) - Includes an interface for the FlatZinc language, enabling it to execute MiniZinc models.
* [OptaPlanner](https://www.optaplanner.org/) - Business planning and resource scheduling optimization solver.

## CSV

*Frameworks and libraries that simplify reading/writing CSV data.*

* [jackson-dataformat-csv](https://github.com/FasterXML/jackson-dataformat-csv) - Jackson extension for reading and writing CSV.
* [opencsv](http://opencsv.sourceforge.net) - Simple CSV parser.
* [Super CSV](https://super-csv.github.io/super-csv/) - Powerful CSV parser with support for Dozer, Joda-Time and Java 8.
* [uniVocity-parsers](https://github.com/uniVocity/univocity-parsers) - One of the fastest and most feature-complete parsers. Also comes with parsers for TSV and fixed-width records.

## Database

*Everything that simplifies interactions with the database.*

* [Apache Phoenix](https://phoenix.apache.org/) - High-performance relational database layer over HBase for low-latency applications.
* [Chronicle Map](https://github.com/OpenHFT/Chronicle-Map) - Efficient, in-memory (opt. persisted to disk), off-heap key-value store.
* [eXist](https://github.com/eXist-db/exist) - A NoSQL document database and application platform.
* [FlexyPool](https://github.com/vladmihalcea/flexy-pool) - Brings metrics and failover strategies to the most common connection pooling solutions.
* [Flyway](https://flywaydb.org/) - Simple database migration tool.
* [H2](https://h2database.com/) - Small SQL database notable for its in-memory functionality.
* [HikariCP](https://github.com/brettwooldridge/HikariCP) - High-performance JDBC connection pool.
* [JDBI](http://jdbi.org/) - Convenient abstraction of JDBC.
* [Jedis](https://github.com/xetorthio/jedis) - Small client for interaction with Redis, with methods for commands.
* [Jest](https://github.com/searchbox-io/Jest) - Client for the Elasticsearch REST API.
* [jetcd](https://github.com/justinsb/jetcd) - Client library for etcd.
* [Jinq](https://github.com/my2iu/Jinq) - Typesafe database queries via symbolic execution of Java 8 Lambdas (on top of JPA or jOOQ).
* [jOOQ](https://www.jooq.org/) - Generates typesafe code based on SQL schema.
* [Liquibase](http://www.liquibase.org/) - Database-independent library for tracking, managing and applying database schema changes.
* [MapDB](http://www.mapdb.org/) - Embedded database engine that provides concurrent collections backed on disk or in off-heap memory.
* [MariaDB4j](https://github.com/vorburger/MariaDB4j/) - Launcher for MariaDB that requires no installation or external dependencies.
* [OrientDB](https://orientdb.com/orientdb/) - Embeddable distributed database written on top of Hazelcast.
* [Presto](https://github.com/prestodb/presto) - Distributed SQL query engine for big data.
* [Querydsl](http://www.querydsl.com/) - Typesafe unified queries.
* [Realm](https://github.com/realm/realm-java) - Mobile database to run directly inside phones, tablets or wearables.
* [Redisson](https://github.com/mrniko/redisson) - Allows for distributed and scalable data structures on top of a Redis server.
* [requery](https://github.com/requery/requery) - A 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.
* [Speedment](https://github.com/speedment/speedment) - Database access library that utilizes Java 8's Stream API for querying.
* [sql2o](https://sql2o.org/) - Thin JDBC wrapper that simplifies database access and provides simple mapping of ResultSets to POJOs.
* [Vibur DBCP](https://www.vibur.org/) - JDBC connection pool library with advanced performance monitoring capabilities.
* [Xodus](https://jetbrains.github.io/xodus/) - Highly concurrent transactional schema-less and ACID-compliant embedded database.

## Data Structures

*Efficient and specific data structures.*

* [Apache Avro](https://avro.apache.org/) - Data interchange format with dynamic typing, untagged data, and absence of manually assigned IDs.
* [Apache Orc](https://orc.apache.org/) - Fast and efficient columnar storage format for Hadoop-based workloads.
* [Apache Parquet](https://parquet.apache.org/) - Columnar storage format based on assembly algorithms from Google's paper on Dremel.
* [Apache Thrift](https://thrift.apache.org/) - Data interchange format that originated at Facebook.
* [Big Queue](https://github.com/bulldog2011/bigqueue) - A big, fast and persistent queue based on memory-mapped files.
* [Persistent Collection](https://pcollections.org/) - Persistent and immutable analogue of the Java Collections Framework.
* [Protobuf](https://github.com/google/protobuf) - Google's data interchange format.
* [SBE](https://github.com/real-logic/simple-binary-encoding) - Simple Binary Encoding, one of the fastest message formats around.
* [Tape](https://github.com/square/tape) - A lightning-fast, transactional, file-based FIFO.
* [Wire](https://github.com/square/wire) - Clean, lightweight protocol buffers.

## Date and Time

*Libraries related to handling date and time.*

* [Almanac Converter](https://github.com/hypotemoose/almanac-converter) - Simple conversion between different calendar systems.
* [iCal4j](https://github.com/ical4j/ical4j) - Parse and build iCalendar [RFC 5545](https://tools.ietf.org/html/rfc5545) data models.
* [ThreeTen-Extra](https://github.com/ThreeTen/threeten-extra) - Additional date-time classes that complement those in JDK 8.
* [Time4J](https://github.com/MenoData/Time4J) - Advanced date and time library.

## Dependency Injection

*Libraries that help to realize the [Inversion of Control](https://en.wikipedia.org/wiki/Inversion_of_control) paradigm.*

* [Apache DeltaSpike](https://deltaspike.apache.org/) - CDI extension framework.
* [Dagger2](https://google.github.io/dagger/) - Compile-time injection framework without reflection.
* [Feather](https://github.com/zsoltherpai/feather) - Ultra-lightweight, JSR-330-compliant dependency injection library.
* [Governator](https://github.com/Netflix/governator) - Extensions and utilities that enhance Google Guice.
* [Guice](https://github.com/google/guice) - Lightweight and opinionated framework that completes Dagger.
* [HK2](https://javaee.github.io/hk2) - Lightweight and dynamic dependency injection framework.

## Development

*Augmentation of the development process at a fundamental level.*

* [AspectJ](https://eclipse.org/aspectj/) - Seamless aspect-oriented programming extension.
* [DCEVM](https://dcevm.github.io/) - JVM modification that allows unlimited redefinition of loaded classes at runtime.
* [Faux Pas](https://github.com/zalando/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](https://github.com/HotswapProjects/HotswapAgent) - Unlimited runtime class and resource redefinition.
* [JavaParser](https://github.com/javaparser/javaparser) - Parse, modify and generate Java code.
* [JavaSymbolSolver](https://github.com/javaparser/javasymbolsolver) - A symbol solver for Java.
* [JRebel ![c]](https://zeroturnaround.com/software/jrebel/) - Instantly reloads code and configuration changes without redeploys.
* [NoException](https://noexception.machinezoo.com/) - Allows checked exceptions in functional interfaces and converts exceptions to Optional return.

## Distributed Applications

*Libraries and frameworks for writing distributed and fault-tolerant applications.*

* [Apache Geode](https://geode.apache.org/) - In-memory data management system that provides reliable asynchronous event notifications and guaranteed message delivery.
* [Apache Storm](https://storm.apache.org/) - Realtime computation system.
* [Apache ZooKeeper](https://zookeeper.apache.org/) - Coordination service with distributed configuration, synchronization, and naming registry for large distributed systems.
* [Atomix](http://atomix.io/atomix/) - Fault-tolerant distributed coordination framework.
* [Axon Framework](http://www.axonframework.org/) - Framework for creating CQRS applications.
* [Copycat](http://atomix.io/copycat/) - Fault-tolerant state machine replication framework.
* [Dropwizard Circuit Breaker](https://github.com/mtakaki/dropwizard-circuitbreaker) - Circuit breaker design pattern for Dropwizard.
* [Failsafe](https://github.com/jhalterman/failsafe) - Simple failure handling with retries and circuit breakers.
* [Hazelcast ![c]](https://hazelcast.org/) - Highly scalable in-memory datagrid with a free open-source version.
* [Hystrix](https://github.com/Netflix/Hystrix) - Provides latency and fault tolerance.
* [JGroups](http://www.jgroups.org/) - Toolkit for reliable messaging and cluster creation.
* [Orbit](http://www.orbit.cloud/) - Virtual actors; adds another level of abstraction to traditional actors.
* [Quasar](https://www.paralleluniverse.co/quasar/) - Lightweight threads and actors for the JVM.
* [resilience4j](https://github.com/resilience4j/resilience4j) - Functional fault tolerance library.
* [Zuul](https://github.com/Netflix/zuul) - A gateway service that provides dynamic routing, monitoring, resiliency, security, and more.

## Distributed Transactions

*Distributed transactions provide a mechanism for ensuring consistency of data updates in the presence of concurrent access and partial failures.*

* [Atomikos](https://www.atomikos.com) - Provides transactions for REST, SOA and microservices with support for JTA and XA.
* [Bitronix](https://github.com/bitronix/btm) - A simple but complete implementation of the JTA 1.1 API.
* [Narayana](http://narayana.io) - Provides support for traditional ACID and compensation transactions, also complies with JTA, JTS and other standards.

## Distribution

*Tools that handle the distribution of applications in native formats.*

* [Bintray ![c]](https://bintray.com/) - Version control for binaries that handle publishing. Compatible with Maven or Gradle, with a free plan for open-source software as well as several business plans.
* [Boxfuse](https://boxfuse.com) - Deployment of JVM applications to AWS using the principles of immutable infrastructure.
* [Capsule](http://www.capsule.io/) - Simple and powerful packaging and deployment. A fat JAR on steroids, or a "Docker for Java" that supports JVM-optimized containers.
* [Central Repository](https://search.maven.org/) - Largest binary component repository available as a free service to the open-source community. Default used by Apache Maven, and available in all other build tools.
* [IzPack](http://izpack.org/) - Setup authoring tool for cross-platform deployments.
* [JitPack](https://jitpack.io/) - Easy-to-use package repository for GitHub. Builds Maven/Gradle projects on demand and publishes ready-to-use packages.
* [Nexus ![c]](https://www.sonatype.com/nexus/solution-overview) - Binary management with proxy and caching capabilities.
* [packr](https://github.com/libgdx/packr/) - Packs JARs, assets and the JVM for native distribution on Windows, Linux and Mac OS X.
* [really-executable-jars-maven-plugin](https://github.com/brianm/really-executable-jars-maven-plugin) - Maven plugin for making self-executing JARs.

## Document Processing

*Libraries that assist with processing office document formats.*

* [Apache POI](https://poi.apache.org/) - Supports OOXML (XLSX, DOCX, PPTX) as well as OLE2 (XLS, DOC or PPT).
* [documents4j](http://documents4j.com) - API for document format conversion using third-party converters such as MS Word.
* [docx4j](https://www.docx4java.org/trac/docx4j) - Create and manipulate Microsoft Open XML files.

## Formal Verification

*Formal-methods tools: proof assistants, model checking, symbolic execution, etc.*

* [CATG](https://github.com/ksen007/janala2) - Concolic unit testing engine. Automatically generates unit tests using formal methods.
* [Checker Framework](https://types.cs.washington.edu/checker-framework/) - Pluggable type systems. Includes nullness types, physical units, immutability types and more.
* [Daikon](https://plse.cs.washington.edu/daikon/) - Detects likely program invariants and generates JML specs based on those invariants.
* [Java Path Finder (JPF)](https://babelfish.arc.nasa.gov/trac/jpf) - JVM formal verification tool containing a model checker and more. Created by NASA.
* [JMLOK 2.0](http://massoni.computacao.ufcg.edu.br/home/jmlok) - Detects inconsistencies between code and JML specification through feedback-directed random tests generation, and suggests a likely cause for each nonconformance detected.
* [KeY](https://key-project.org/) - Formal software development tool that aims to integrate design, implementation, formal specification, and formal verification of object-oriented software as seamlessly as possible. Uses JML for specification and symbolic execution for verification.
* [OpenJML](https://openjml.github.io/) - Translates JML specifications into SMT-LIB format and passes the proof problems implied by the program to backend solvers.

## Functional Programming

*Libraries that facilitate functional programming.*

* [cyclops-react](https://github.com/aol/cyclops-react) - Monad and stream utilities, comprehensions, pattern matching, functional extensions for all JDK collections, future streams, trampolines and much more.
* [derive4j](https://github.com/derive4j/derive4j) - Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching and morphisms.
* [Fugue](https://bitbucket.org/atlassian/fugue) - Functional extensions to Guava.
* [Functional Java](http://www.functionaljava.org) - Implements numerous basic and advanced programming abstractions that assist composition-oriented development.
* [jOOλ](https://github.com/jOOQ/jOOL) - 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](https://github.com/poetix/protonpack) - Collection of stream utilities.
* [StreamEx](https://github.com/amaembo/streamex) - Enhances Java 8 Streams.
* [Vavr](http://www.vavr.io/) - Functional component library that provides persistent data types and functional control structures.

## Game Development

*Frameworks that support the development of games.*

* [jMonkeyEngine](https://jmonkeyengine.org/) - Game engine for modern 3D development.
* [libGDX](https://libgdx.badlogicgames.com/) - All-round cross-platform, high-level framework.
* [LWJGL](https://www.lwjgl.org/) - Robust framework that abstracts libraries like OpenGL/CL/AL.
* [FXGL](https://almasb.github.io/FXGL/) - JavaFX Game Development Framework.

## Geospatial

*Libraries for working with geospatial data and algorithms.*

* [Apache SIS](https://sis.apache.org/) - Library for developing geospatial applications.
* [Geo](https://github.com/davidmoten/geo/) - GeoHash utilities in Java.
* [Geotoolkit.org](http://www.geotoolkit.org/) - Library for developing geospatial applications. Built on top of the Apache SIS project.
* [GeoTools](http://geotools.org/) - Library that provides tools for geospatial data.
* [GraphHopper](https://github.com/graphhopper/graphhopper) - Road-routing engine. Used as a Java library or standalone web service.
* [H2GIS](http://www.h2gis.org/) - A spatial extension of the H2 database.
* [Jgeohash](https://astrapi69.github.io/jgeohash/) - Library for using the GeoHash algorithm.
* [Mapsforge](https://github.com/mapsforge/mapsforge/) - Map rendering based on OpenStreetMap data.
* [Spatial4j](https://github.com/locationtech/spatial4j/) - General-purpose spatial/geospatial library.

## GUI

*Libraries to create modern graphical user interfaces.*

* [JavaFX](https://www.oracle.com/technetwork/java/javase/overview/javafx-overview-2158620.html) - The successor of Swing.
* [Scene Builder](https://gluonhq.com/open-source/scene-builder/) - Visual layout tool for JavaFX applications.
* [SWT](https://www.eclipse.org/swt/) - The Standard Widget Toolkit, a graphical widget toolkit.

## High Performance

*Everything about high-performance computation, from collections to specific libraries.*

* [Agrona](https://github.com/real-logic/Agrona) - Data structures and utility methods that are common in high-performance applications.
* [Disruptor](https://lmax-exchange.github.io/disruptor/) - Inter-thread messaging library.
* [Eclipse Collections](https://github.com/eclipse/eclipse-collections) - Collections framework inspired by Smalltalk.
* [fastutil](http://fastutil.di.unimi.it/) - Fast and compact type-specific collections.
* [HPPC](https://labs.carrotsearch.com/hppc.html) - Primitive collections.
* [JCTools](https://github.com/JCTools/JCTools) - Concurrency tools currently missing from the JDK.
* [Koloboke](https://github.com/OpenHFT/Koloboke) - Hash sets and hash maps.

## HTTP Clients

*Libraries that assist with creating HTTP requests and/or binding responses.*

* [Async Http Client](https://github.com/AsyncHttpClient/async-http-client) - Asynchronous HTTP and WebSocket client library.
* [Feign](https://github.com/Netflix/feign) - HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.
* [OkHttp](https://square.github.io/okhttp/) - HTTP+SPDY client.
* [restQL-core](https://github.com/B2W-BIT/restQL-core) - Microservice query language that fetches information from multiple services.
* [Retrofit](https://square.github.io/retrofit/) - Typesafe REST client.
* [Ribbon](https://github.com/Netflix/ribbon) - Client-side IPC library that is battle-tested in cloud.
* [Riptide](https://github.com/zalando/riptide) - Client-side response routing for Spring's RestTemplate.

## Hypermedia Types

*Libraries that handle serialization to hypermedia types.*

* [JSON-LD](https://github.com/jsonld-java/jsonld-java) - JSON-LD implementation.
* [Siren4J](https://github.com/eserating/siren4j) - Library for the Siren specification.

## IDE

*Integrated development environments that try to simplify several aspects of development.*

* [Eclipse](https://www.eclipse.org/) - Established open-source project with support for lots of plugins and languages.
* [IntelliJ IDEA ![c]](https://www.jetbrains.com/idea/) - Supports many JVM languages and provides good options for Android development. The commercial edition targets the enterprise sector.
* [NetBeans](https://netbeans.org/) - Provides integration for several Java SE and EE features, from database access to HTML5.

## Imagery

*Libraries that assist with the creation, evaluation or manipulation of graphical images.*

* [Imgscalr](https://github.com/thebuzzmedia/imgscalr) - Simple, efficient and hardware-accelerated image-scaling library implemented in pure Java 2D.
* [Tess4J](https://github.com/nguyenq/tess4j) - A JNA wrapper for Tesseract OCR API.
* [Thumbnailator](https://github.com/coobird/thumbnailator) - High-quality thumbnail generation library.
* [TwelveMonkeys](https://github.com/haraldk/TwelveMonkeys) - Collection of plugins that extend the number of supported image file formats.
* [ZXing](https://github.com/zxing/zxing) - Multi-format 1D/2D barcode image processing library.

## JSON

*Libraries for serializing and deserializing JSON to and from Java objects.*

* [Genson](https://owlike.github.io/genson/) - Powerful and easy-to-use Java-to-JSON conversion library.
* [Gson](https://github.com/google/gson) - Serializes objects to JSON and vice versa. Good performance with on-the-fly usage.
* [HikariJSON](https://github.com/brettwooldridge/HikariJSON) - High-performance JSON parser, 2x faster than Jackson.
* [Jackson-datatype-money](https://github.com/zalando/jackson-datatype-money) - Open-source Jackson module to support JSON serialization and deserialization of JavaMoney data types.
* [Jackson](https://github.com/FasterXML/jackson) - Similar to GSON, but offers performance gains if you need to instantiate the library more often.
* [JSON-io](https://github.com/jdereg/json-io) - Convert Java to JSON. Convert JSON to Java. Pretty print JSON. Java JSON serializer.
* [jsoniter](http://jsoniter.com) - Fast and flexible library with iterator and lazy parsing API.
* [LoganSquare](https://github.com/bluelinelabs/LoganSquare) - JSON parsing and serializing library based on Jackson's streaming API. Outperforms GSON & Jackson's library.
* [Moshi](https://github.com/square/moshi) - Modern JSON library, less opinionated and uses built-in types like List and Map.
* [Yasson](https://github.com/eclipse/yasson) - Binding layer between classes and JSON documents similar to JAXB.

## JSON Processing

*Libraries for processing data in JSON format.*

* [fastjson](https://github.com/alibaba/fastjson) - Very fast processor with no additional dependencies and full data binding.
* [Jolt](https://github.com/bazaarvoice/jolt) - JSON to JSON transformation tool.
* [JsonPath](https://github.com/jayway/JsonPath) - Extract data from JSON using XPATH-like syntax.
* [JsonSurfer](https://github.com/jsurfer/JsonSurfer) - Streaming JsonPath processor dedicated to processing big and complicated JSON data.

## JVM and JDK

*Current implementations of the JVM/JDK.*

* [Avian](https://github.com/ReadyTalk/avian) - JVM with both JIT and AOT modes. Includes an iOS port.
* [OpenJ9](https://github.com/eclipse/openj9) - High performance, enterprise calibre, flexibly licensed, openly governed cross platform Java Virtual Machine extending and augmenting the runtime technology components from the Eclipse OMR and OpenJDK project.
* [OpenJDK](http://openjdk.java.net/) - Open-source implementation for Linux.
* [ParparVM](https://github.com/codenameone/CodenameOne/tree/master/vm) - VM with non-blocking, concurrent GC for iOS.
* [Zulu OpenJDK 9](https://zulu.org/zulu-9-pre-release-downloads/) - Early-access OpenJDK 9 builds for Windows, Linux, and Mac OS X.
* [Zulu OpenJDK](https://www.azul.com/downloads/zulu/) - OpenJDK builds for Windows, Linux, and Mac OS X through Java 8.

## Logging

*Libraries that log the behavior of an application.*

* [Apache Log4j 2](https://logging.apache.org/log4j/) - Complete rewrite with a powerful plugin and configuration architecture.
* [Graylog](https://www.graylog.org/) - Open-source aggregator suited for extended role and permission management.
* [Kibana](https://www.elastic.co/products/kibana) - Analyzes and visualizes log files. Some features require payment.
* [Logback](https://logback.qos.ch/) - Robust logging library with interesting configuration options via Groovy.
* [Logbook](https://github.com/zalando/logbook) - Extensible, open-source library for HTTP request and response logging.
* [Logstash](https://www.elastic.co/products/logstash) - Tool for managing log files.
* [SLF4J](https://www.slf4j.org/) - Abstraction layer/simple logging facade.
* [tinylog](http://www.tinylog.org/) - Lightweight logging framework with static logger class.
* [Tracer](https://github.com/zalando/tracer) - Call tracing and log correlation in distributed systems.

## Machine Learning

*Tools that provide specific statistical algorithms for learning from data.*

* [Apache Flink](https://flink.apache.org/) - Fast, reliable, large-scale data processing engine.
* [Apache Mahout](https://mahout.apache.org/) - Scalable algorithms focused on collaborative filtering, clustering and classification.
* [Apache Spark](https://spark.apache.org/) - Data analytics cluster-computing framework.
* [DatumBox](http://www.datumbox.com) - Provides several algorithms and pre-trained models for natural language processing.
* [DeepDive](http://deepdive.stanford.edu) - Creates structured information from unstructured data and integrates it into an existing database.
* [Deeplearning4j](https://deeplearning4j.org/) - Distributed and multi-threaded deep learning library.
* [H2O](https://www.h2o.ai/) - Analytics engine for statistics over big data.
* [JSAT](https://github.com/EdwardRaff/JSAT) - Algorithms for pre-processing, classification, regression, and clustering with support for multi-threaded execution.
* [Oryx 2](https://github.com/OryxProject/oryx) - Framework for building real-time, large-scale machine learning applications. Includes end-to-end applications for collaborative filtering, classification, regression, and clustering.
* [Smile](https://haifengl.github.io/smile/) - The Statistical Machine Intelligence and Learning Engine provides a set of machine learning algorithms and a visualization library.
* [Weka](https://www.cs.waikato.ac.nz/ml/weka/) - Collection of algorithms for data mining tasks ranging from pre-processing to visualization.

## Messaging

*Tools that help send messages between clients to ensure protocol independency.*

* [Aeron](https://github.com/real-logic/Aeron) - Efficient, reliable, unicast and multicast message transport.
* [Apache ActiveMQ](https://activemq.apache.org/) - Message broker that implements JMS and converts synchronous to asynchronous communication.
* [Apache Camel](https://camel.apache.org/) - Glues together different transport APIs via Enterprise Integration Patterns.
* [Apache Kafka](https://kafka.apache.org/) - High-throughput distributed messaging system.
* [Hermes](http://hermes.allegro.tech) - Fast and reliable message broker built on top of Kafka.
* [JeroMQ](https://github.com/zeromq/jeromq) - Implementation of ZeroMQ.
* [Nakadi](https://github.com/zalando/nakadi) - Provides a RESTful API on top of Kafka.
* [RocketMQ](https://github.com/alibaba/RocketMQ) - A fast, reliable, and scalable distributed messaging platform.
* [Smack](https://github.com/igniterealtime/Smack/) - Cross-platform XMPP client library.

## Miscellaneous

*Everything else.*

* [Codename One](https://www.codenameone.com/) - Cross-platform solution for writing native mobile apps.
* [CQEngine](https://github.com/npgall/cqengine) - Ultra-fast, SQL-like queries on Java collections.
* [Design Patterns](https://github.com/iluwatar/java-design-patterns) - Implementation and explanation of the most common design patterns.
* [Failsafe](https://github.com/jhalterman/failsafe) - Simple failure handling with retries and circuit breakers.
* [FF4J](http://www.ff4j.org/) - Feature Flags for Java.
* [J2ObjC](https://github.com/google/j2objc) - Java-to-Objective-C translator for porting Android libraries to iOS.
* [JavaX](http://javax.ai1.lol/) - Reinventing and extending Java with a focus on simplicity.
* [JBake](http://jbake.org) - Static website generator.
* [JBot](https://github.com/ramswaroop/jbot) - Framework for building chatbots.
* [Jimfs](https://github.com/google/jimfs) - In-memory file system.
* [Joda-Money](http://www.joda.org/joda-money/) - Basic currency and money classes and algorithms not provided by the JDK.
* [JPad](http://jpad.io/) - Snippet runner.
* [Lanterna](https://github.com/mabe02/lanterna) - Easy console text-GUI library, similar to curses.
* [LightAdmin](http://lightadmin.org/) - Pluggable CRUD UI library for rapid application development.
* [Maven Wrapper](https://github.com/takari/maven-wrapper) - Analogue of Gradle Wrapper for Maven, allows build projects without installing maven.
* [Membrane Service Proxy](https://github.com/membrane/service-proxy) - An open-source, reverse-proxy framework written in Java.
* [Multi-OS Engine](https://software.intel.com/en-us/multi-os-engine) - An open-source, cross-platform engine to develop native mobile (iOS, Android, etc.) apps.
* [Modern Java - A Guide to Java 8](https://github.com/winterbe/java8-tutorial) - Popular Java 8 guide.
* [Modernizer](https://github.com/andrewgaul/modernizer-maven-plugin) - Detect uses of legacy Java APIs.
* [OpenRefine](http://openrefine.org/) - Tool for working with messy data: cleaning, transforming, extending it with web services and linking it to databases.
* [Polyglot for Maven](https://github.com/takari/polyglot-maven/) - Extensions for Maven 3.3.1+ that allows writing the POM model in dialects other than XML.
* [Smooks](https://github.com/smooks/smooks) - Extensible framework for building applications that process data which means bindings, transformations, message processing and enrichment.
* [Togglz](https://www.togglz.org/) - Implementation of the Feature Toggles pattern.
* [TypeTools](https://github.com/jhalterman/typetools) - Tools for resolving generic types.
* [XMLBeam](https://github.com/SvenEwald/xmlbeam) - Processes XML by using annotations or XPath within code.

## Microservice

*Tools for managing microservices: i.e., creation, coordination or discovery.*

* [Apollo](https://spotify.github.io/apollo/) - Libraries for writing composable microservices.
* [consul-api](https://github.com/Ecwid/consul-api) - Client for the [Consul](https://www.consul.io/) API: a distributed, highly available and datacenter-aware registry/discovery service.
* [Eureka](https://github.com/Netflix/eureka) - REST-based service registry for resilient load balancing and failover.
* [Lagom](https://www.lightbend.com/lagom) - Framework for creating microservice-based systems.

## Monitoring

*Tools that monitor applications in production.*

* [AppDynamics ![c]](https://www.appdynamics.com/) - Performance monitor.
* [Automon](https://github.com/stevensouza/automon) - Combines the power of AOP with monitoring and/or logging tools.
* [Failsafe Actuator](https://github.com/zalando-incubator/failsafe-actuator) - Out of the box monitoring of Failsafe Circuit Breaker in Spring-Boot environment.
* [BugSnag ![c]](https://www.bugsnag.com/) - Exception and error monitoring with a integration of several third party tools for a better workflow and a free hobbyist tier.
* [Glowroot](https://glowroot.org/) - Open-source Java APM.
* [Instrumental ![c]](https://instrumentalapp.com) - Real-time Java application performance monitoring. A commercial service with free development accounts.
* [JavaMelody](https://github.com/javamelody/javamelody) - Performance monitoring and profiling.
* [jmxtrans](https://github.com/jmxtrans/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.
* [Jolokia](https://jolokia.org/) - JMX over REST.
* [Kamon](http://www.kamon.io/) - Tool for monitoring applications running on the JVM.
* [Metrics](http://metrics.dropwizard.io/) - Expose metrics via JMX or HTTP and send them to a database.
* [New Relic ![c]](https://newrelic.com/) - Performance monitor.
* [nudge4j](https://github.com/lorenzoongithub/nudge4j) - Remote developer console from the browser for Java 8 via bytecode injection.
* [OverOps ![c]](https://www.overops.com/) - In-production error monitoring and debugging.
* [Pinpoint](https://github.com/naver/pinpoint) - Open-source APM tool.
* [Prometheus](https://prometheus.io/) - Provides a multi-dimensional data model, DSL, autonomous server nodes and much more.
* [SPM ![c]](https://sematext.com/spm/) - Performance monitor with distributing transaction tracing for JVM apps.
* [Stagemonitor](https://github.com/stagemonitor/stagemonitor) - Open-source performance monitoring and transaction tracing for JVM apps.
* [Sysmon](https://github.com/palantir/Sysmon) - Lightweight platform monitoring tool for Java VMs.

## Native
*For working with platform-specific native libraries.*

* [JavaCPP](https://github.com/bytedeco/javacpp) - Provides efficient and easy access to native C++.
* [JNA](https://github.com/java-native-access/jna) - Work with native libraries without writing JNI. Also provides interfaces to common system libraries.
* [JNR](https://github.com/jnr/jnr-ffi) - 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

*Libraries that specialize in processing text.*

* [CogCompNLP](https://github.com/CogComp/cogcomp-nlp) - Provides common annotators for plain text input.
* [CoreNLP](https://nlp.stanford.edu/software/corenlp.shtml) - Provides a set of fundamental tools for tasks like tagging, named entity recognition, and sentiment analysis.
* [DKPro](https://dkpro.github.io/) - Collection of reusable NLP tools for linguistic pre-processing, machine learning, lexical resources, etc.
* [LingPipe](http://alias-i.com/lingpipe/) - Toolkit for tasks ranging from POS tagging to sentiment analysis.

## Networking

*Libraries for building network servers.*

* [Comsat](https://github.com/puniverse/comsat) - Integrates standard Java web-related APIs with Quasar fibers and actors.
* [Finagle](https://github.com/twitter/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.
* [Grizzly](https://javaee.github.io/grizzly) - NIO framework. Used as a network layer in Glassfish.
* [gRPC](https://github.com/grpc/grpc-java) - RPC framework based on protobuf and HTTP/2.
* [KryoNet](https://github.com/EsotericSoftware/kryonet) - Provides a clean and simple API for efficient TCP and UDP client/server network communication using NIO and Kryo.
* [MINA](https://mina.apache.org/) - Abstract, event-driven async I/O API for network operations over TCP/IP and UDP/IP via Java NIO.
* [Netty](https://netty.io/) - Framework for building high-performance network applications.
* [Nifty](https://github.com/facebook/nifty) - Implementation of Thrift clients and servers on Netty.
* [Undertow](http://undertow.io/) - Web server providing both blocking and non-blocking APIs based on NIO. Used as a network layer in WildFly.
* [urnlib](https://github.com/slub/urnlib) - Represent, parse and encode URNs, as in RFC 2141.

## ORM

*APIs that handle the persistence of objects.*

* [Apache Cayenne](https://cayenne.apache.org/) - Provides a clean, static API for data access. Also includes a GUI Modeler for working with database mappings, and DB reverse engineering and generation.
* [Ebean](https://ebean-orm.github.io/) - Provides simple and fast data access.
* [EclipseLink](https://www.eclipse.org/eclipselink/) - Supports a number of persistence standards: JPA, JAXB, JCA and SDO.
* [Hibernate](http://hibernate.org/orm/) - Robust and widely used, with an active community.
* [MyBatis](http://www.mybatis.org/mybatis-3/) - Couples objects with stored procedures or SQL statements.
* [SimpleFlatMapper](https://github.com/arnaudroger/SimpleFlatMapper) - Simple database and CSV mapper.

## PaaS

*Java platform as a service.*

* [AWS Elastic Beanstalk ![c]](https://aws.amazon.com/elasticbeanstalk/) - AWS-based, with support for Tomcat and Jetty.
* [AWS Lambda ![c]](https://aws.amazon.com/lambda/) - Serverless computation.
* [Google App Engine ![c]](https://cloud.google.com/) - PaaS on Google's infrastructure.
* [Heroku ![c]](https://www.heroku.com/) - Abstract computing environments.
* [Jelastic ![c]](https://jelastic.com/) - Supports Tomcat, Jetty, GlassFish, JBoss, TomEE and WildFly.
* [OpenShift Enterprise ![c]](https://www.openshift.com/) - On-premise solution.

## PDF

*Tools to help with PDF file creation.*

* [Apache FOP](https://xmlgraphics.apache.org/fop/) - Creates PDFs from XSL-FO.
* [Apache PDFBox](https://pdfbox.apache.org/) - Toolbox for creating and manipulating PDFs.
* [Dynamic Jasper](http://dynamicjasper.com/) - Abstraction layer to JasperReports.
* [DynamicReports](http://dynamicreports.org/) - Simplifies JasperReports.
* [flyingsaucer](https://github.com/flyingsaucerproject/flyingsaucer) - XML/XHTML and CSS 2.1 renderer.
* [iText ![c]](https://itextpdf.com/) - Creates PDF files programmatically.
* [JasperReports](https://community.jaspersoft.com/project/jasperreports-library) - Complex reporting engine.

## Performance analysis

*Tools for performance analysis, profiling and benchmarking.*

* [fastThread ![c]](http://fastthread.io) - Analyze and visualize thread dumps with a free cloud-based upload interface.
* [GCeasy ![c]](http://gceasy.io) - Tool to analyze and visualize GC logs. It provides a free cloud-based upload interface.
* [honest-profiler](https://github.com/RichardWarburton/honest-profiler) - A low-overhead, bias-free sampling profiler.
* [jHiccup](https://github.com/giltene/jHiccup) - Logs and records platform JVM stalls.
* [JITWatch](https://github.com/AdoptOpenJDK/jitwatch) - Analyze the JIT compiler optimisations made by the HotSpot JVM.
* [JMH](http://openjdk.java.net/projects/code-tools/jmh/) - a Java harness for building, running, and analysing nano/micro/milli/macro benchmarks written in Java and other languages targeting the JVM.
* [JProfiler ![c]](https://www.ej-technologies.com/products/jprofiler/overview.html) - Database profiling for JDBC, JPA and NoSQL, with JEE support.
* [LatencyUtils](https://github.com/LatencyUtils/LatencyUtils) - Utilities for latency measurement and reporting.
* [XRebel ![c]](https://zeroturnaround.com/software/xrebel/) - Real-time profiling for web applications, with an in-browser widget.
* [YourKit Java Profiler ![c]](https://www.yourkit.com/features/) - Profiler for any application running on the JVM.

## Platform

*Frameworks that are suites of multiple libraries encompassing several categories.*

* [CUBA Platform](https://cuba-platform.com) - High-level framework for developing enterprise applications with a rich web interface, based on Spring, EclipseLink and Vaadin.
* [Light-Java](https://github.com/networknt/light-java) - A fast, lightweight and productive microservices framework with built-in [security](https://github.com/networknt/light-oauth2).
* [Orienteer](https://github.com/OrienteerBAP/Orienteer) - Open-source business application platform for rapid configuration/development of CRM, ERP, LMS and other applications.
* [Spring](https://spring.io/projects) - Provides many packages for dependency injection, aspect-oriented programming, security, etc.

## Reactive libraries

*Libraries for developing reactive applications.*

* [Akka](https://akka.io) - Toolkit and runtime for building concurrent, distributed, fault-tolerant and event-driven applications.
* [Reactive Streams](https://github.com/reactive-streams/reactive-streams-jvm/) - Provides a standard for asynchronous stream processing with non-blocking backpressure.
* [Reactor](https://projectreactor.io/) - Library for building reactive fast-data applications.
* [vert.x](http://vertx.io/) - Polyglot event-driven application framework.

## REST Frameworks

*Frameworks specifically for creating RESTful services.*

* [Dropwizard](https://dropwizard.github.io/dropwizard/) - Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.
* [Jersey](https://jersey.github.io/) - JAX-RS reference implementation.
* [Microserver](https://github.com/aol/micro-server) — 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.
* [Rapidoid](https://www.rapidoid.org/) - A simple, secure and extremely fast framework consisting of an embedded HTTP server, GUI components and dependency injection.
* [rest.li](https://github.com/linkedin/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.
* [RESTEasy](https://resteasy.jboss.org/) - Fully certified and portable implementation of the JAX-RS specification.
* [RestExpress](https://github.com/RestExpress/RestExpress) - Thin wrapper on the JBoss Netty HTTP stack that provides scaling and performance.
* [Restlet Framework](https://github.com/restlet/restlet-framework-java/) - Pioneering framework with powerful routing and filtering capabilities, and a unified client and server API.
* [Spark](http://sparkjava.com/) - Sinatra inspired framework.
* [Crnk](http://www.crnk.io/) - 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.

## Science

*Libraries for scientific computing, analysis and visualization.*

* [DataMelt](http://jwork.org/dmelt/) - Environment for scientific computation, data analysis and data visualization.
* [Erdos](https://github.com/Erdos-Graph-Framework/Erdos) - Modular, light and easy graph framework for theoretic algorithms.
* [GraphStream](http://graphstream-project.org/) - Library for modeling and analyzing dynamic graphs.
* [JGraphT](https://github.com/jgrapht/jgrapht) - Graph library that provides mathematical graph-theory objects and algorithms.
* [JGraphX](https://github.com/jgraph/jgraphx) - Library for visualizing (mainly Swing) and interacting with node-edge graphs.
* [Mines Java Toolkit](https://github.com/MinesJTK/jtk) - Library for geophysical scientific computation, visualization and digital signal analysis.
* [Morpheus](http://www.zavtech.com/morpheus/docs/) - 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](https://github.com/lwhite1/tablesaw) - Includes a data-frame, an embedded column store, and hundreds of methods to transform, summarize, or filter data.

## Search

*Engines that index documents for search and analysis.*

* [Apache Lucene](https://lucene.apache.org/) - High-performance, full-featured, cross-platform, text search engine library.
* [Apache Solr](https://lucene.apache.org/solr/) - Enterprise search engine optimized for high-volume traffic.
* [Elasticsearch](https://www.elastic.co/) - Distributed, multitenant-capable, full-text search engine with a RESTful web interface and schema-free JSON documents.

## Security

*Libraries that handle security, authentication, authorization or session management.*

* [Apache Shiro](https://shiro.apache.org/) - Performs authentication, authorization, cryptography and session management.
* [Bouncy Castle](https://www.bouncycastle.org/java.html) - All-purpose cryptographic library and JCA provider offering a wide range of functions, from basic helpers to PGP/SMIME operations.
* [Cryptomator](https://cryptomator.org/) - Multiplatform, transparent, client-side encryption of files in the cloud.
* [Hdiv](https://github.com/hdiv/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](https://github.com/jwtk/jjwt) - JSON web token for Java and Android.
* [Keycloak](https://keycloak.jboss.org/) - Integrated SSO and IDM for browser apps and RESTful web services.
* [Keyczar](https://github.com/google/keyczar) - Easy-to-use, safe encryption framework with key versioning.
* [Keywhiz](https://github.com/square/keywhiz) - System for distributing and managing secrets.
* [Nbvcxz](https://github.com/GoSimpleLLC/nbvcxz) - Advanced password strength estimation.
* [OACC](http://oaccframework.org/) - Provides permission-based authorization services.
* [pac4j](https://github.com/pac4j/pac4j) - Security engine.
* [PicketLink](http://picketlink.org/) - Umbrella project for security and identity management.
* [Vault](https://www.vaultproject.io/) - 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.

## Serialization

*Libraries that handle serialization with high efficiency.*

* [FlatBuffers](https://github.com/google/flatbuffers) - Memory-efficient serialization library that can access serialized data without unpacking and parsing it.
* [FST](https://github.com/RuedigerMoeller/fast-serialization) - JDK-compatible, high-performance object graph serialization.
* [Kryo](https://github.com/EsotericSoftware/kryo) - Fast and efficient object graph serialization framework.
* [MessagePack](https://github.com/msgpack/msgpack-java) - Efficient binary serialization format.
* [PHP Serializer](https://github.com/marcospassos/java-php-serializer) - Serializing objects in the PHP serialization format.

## Server

*Servers specifically used to deploy applications.*

* [Apache Tomcat](https://tomcat.apache.org/) - Robust, all-round server for Servlet and JSP.
* [Apache TomEE](https://tomee.apache.org/) - Tomcat plus Java EE.
* [Jetty](https://www.eclipse.org/jetty/) - Provides a Web server and javax.servlet container, plus support for HTTP/2, WebSocket, OSGi, JMX, JNDI, JAAS and many other integrations.
* [nanohttpd](https://github.com/NanoHttpd/nanohttpd) - Tiny, easily embeddable HTTP server.
* [WebSphere Liberty](https://developer.ibm.com/wasdev/) - Lightweight, modular server developed by IBM.
* [WildFly](http://www.wildfly.org/) - Formerly known as JBoss and developed by Red Hat with extensive Java EE support.

## Template Engine

*Tools that substitute expressions in a template.*

* [Handlebars.java](https://jknack.github.io/handlebars.java/) - Logicless and semantic Mustache templates.
* [Jtwig](http://jtwig.org/) - Modular, configurable and fully tested template engine.
* [Jade4J](https://github.com/neuland/jade4j) - Implementation of jade.
* [Pebble](http://www.mitchellbosecke.com/pebble/home) - Inspired by Twig and separates itself with it's inheritance feature and it's easy-to-read syntax. It ships with built-in autoescaping for security and it includes integrated support for internationalization.
* [Thymeleaf](http://www.thymeleaf.org/) - Aims to be a substitute for JSP and works for XML files.

## Testing

*Tools that test from model to the view.*

### Asynchronous

*Tools that simplify testing asynchronous services.*

* [Awaitility](https://github.com/jayway/awaitility) - DSL for synchronizing asynchronous operations.
* [ConcurrentUnit](https://github.com/jhalterman/concurrentunit) - Toolkit for testing multi-threaded and asynchronous applications.
* [GreenMail](http://www.icegreen.com/greenmail/) - In-memory email server for integration testing. Supports SMTP, POP3 and IMAP including SSL.
* [Hoverfly Java](https://github.com/SpectoLabs/hoverfly-java) - Native bindings for Hoverfly a proxy which allows you to simulate HTTP services.
* [REST Assured](https://github.com/jayway/rest-assured) - DSL for easy testing of REST/HTTP services.

### BDD

*Testing for the software development process that emerged from TDD and was heavily influenced by DDD and OOAD.*

* [Cucumber](https://github.com/cucumber/cucumber-jvm) - Provides a way to describe features in a plain language which customers can understand.
* [Cukes-REST](https://github.com/ctco/cukes-rest) - A collection of Gherkin steps for REST-service testing using Cucumber.
* [J8Spec](https://github.com/j8spec/j8spec/) - Follows a Jasmine-like syntax.
* [JBehave](http://jbehave.org/) - Extensively configurable framework that describes stories.
* [JGiven](http://jgiven.org) - Provides a fluent API which allows for simpler composition.
* [Lamdba Behave](https://github.com/RichardWarburton/lambda-behave) - Aims to provide a fluent API to write tests in long and descriptive sentences that read like plain English.

### Fixtures

*Everything related to the creation and handling of random data.*

* [Beanmother](https://github.com/keepcosmos/beanmother) - Sets up beans from YAML fixtures.
* [Fixture Factory](https://github.com/six2six/fixture-factory) - Generates fake objects from a template.
* [JFairy](https://github.com/Codearte/jfairy) - Fake data generator.
* [Randomized Testing](https://github.com/randomizedtesting/randomizedtesting) - JUnit test runner and plugins for running JUnit tests with pseudo-randomness.

### Frameworks

*Provide environments to run tests for a specific use case.*

* [ArchUnit](https://github.com/TNG/ArchUnit) - Test library for specifying and asserting architecture rules.
* [Apache JMeter](http://jmeter.apache.org/) - Functional testing and performance measurements.
* [Arquillian](http://arquillian.org/) - Integration and functional testing platform for Java EE containers.
* [Citrus](https://citrusframework.org/) - Integration testing framework that focuses on both client- and server-side messaging.
* [Gatling](https://gatling.io/) - Load testing tool designed for ease of use, maintainability and high performance.
* [JUnit](http://junit.org/) - Common testing framework.
* [TestNG](http://testng.org/) 💀 - Testing framework inspired by JUnit and NUnit, with different functionalities.
* [PIT](http://pitest.org) - Fast mutation-testing framework for evaluating fault-detection abilities of existing JUnit or TestNG test suites.
* [Pact JVM](https://github.com/DiUS/pact-jvm/) - Consumer-driven contract testing.

### Matchers

*Libraries that provide custom matchers.*

* [AssertJ](https://joel-costigliola.github.io/assertj/) - Fluent assertions that improve readability.
* [JSONAssert](http://jsonassert.skyscreamer.org/) - Simplifies testing JSON strings.
* [Truth](https://github.com/google/truth) - Google's assertion and proposition framework.

### Miscellaneous

*Other stuff related to testing.*

* [Mutability Detector](https://github.com/MutabilityDetector/MutabilityDetector) - Reports whether instances of a given class are immutable.
* [raml-tester](https://github.com/nidi3/raml-tester) - Tests if a request/response matches a given RAML definition.
* [TestContainers](https://github.com/testcontainers/testcontainers-java) - Provides throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.
* [pojo-tester](http://www.pojo.pl/) - Automatically performs tests on basic POJO methods.

### Mocking

*Tools which mock collaborators to help testing single, isolated units.*

* [JMockit](http://jmockit.org/) - Integration testing, API mocking and faking, and code coverage.
* [Mockito](https://github.com/mockito/mockito) - Mocking framework that lets you write tests with a clean and simple API.
* [MockServer](https://www.mock-server.com/) - Allows mocking of systems integrated with HTTPS.
* [Moco](https://github.com/dreamhead/moco) - Concise web services for stubs and mocks.
* [PowerMock](https://github.com/jayway/powermock) - Mocks static methods, constructors, final classes and methods, private methods, and removal of static initializers.
* [WireMock](http://wiremock.org/) - Stubs and mocks web services.

### Parameterization

*Simplifies the writing of parameterized tests.*

* [Burst](https://github.com/square/burst) - A unit testing library for varying test data.
* [junit-dataprovider](https://github.com/TNG/junit-dataprovider) - A TestNG-like data provider/runner for JUnit.
* [JUnitParams](https://pragmatists.github.io/JUnitParams/) - Creates readable and maintainable parametrised tests.

## Utility

*Libraries which provide general utility functions.*

* [Apache Commons](https://commons.apache.org/) - Provides configuration, validation, collections, file uploading, XML processing and other general-purpose functions.
* [cactoos](http://www.cactoos.org) - Collection of object-oriented primitives.
* [CRaSH](http://www.crashub.org) - Provides a shell into a JVM that's running CRaSH. Used by Spring Boot and others.
* [Dex](https://github.com/PatMartin/Dex) - Java/JavaFX tool capable of powerful ETL and data visualization.
* [Embulk](http://www.embulk.org/) - Bulk data loader that helps data transfer between various databases, storages, file formats, and cloud services.
* [Gephi](https://github.com/gephi/gephi/) - Cross-platform for visualizing and manipulating large graph networks.
* [Guava](https://github.com/google/guava) - Collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and more.
* [JADE](http://jade.tilab.com/) - Framework and environment for building and debugging multi-agent systems.
* [JavaVerbalExpressions](https://github.com/VerbalExpressions/JavaVerbalExpressions) - Library that helps with constructing difficult regular expressions.
* [JGit](https://eclipse.org/jgit/) - A lightweight, pure Java library implementing the Git version control system.
* [minio-java](https://github.com/minio/minio-java) - Provides simple APIs to access any Amazon S3-compatible object storage server.
* [Protégé](https://protege.stanford.edu/) - Provides an ontology editor and a framework to build knowledge-based systems.
* [Underscore-java](https://github.com/javadev/underscore-java) - Port of Underscore.js functions.

## Version Managers

*Utilities that help create the development shell environment and switch between different Java versions.*

* [jabba](https://github.com/shyiko/jabba) - Java Version Manager inspired by nvm. Supports Mac OS X, Linux and Windows.
* [jenv](https://github.com/gcuisinier/jenv) - Java Version Manager inspired by rbenv. Can configure globally or per project. Tested on Debian and Mac OS X.
* [SDKMan](https://github.com/sdkman/sdkman-cli) - Java Version Manager inspired by RVM and rbenv. Supports UNIX-based platforms and Windows.

## Web Crawling

*Libraries that analyze the content of websites.*

* [Apache Nutch](https://nutch.apache.org/) - Highly extensible, highly scalable web crawler for production environments.
* [Crawler4j](https://github.com/yasserg/crawler4j) - Simple and lightweight web crawler.
* [jsoup](https://jsoup.org/) - Scrapes, parses, manipulates and cleans HTML.
* [StormCrawler](http://stormcrawler.net/) - SDK for building low-latency and scalable web crawlers.

## Web Frameworks

*Frameworks that handle the communication between the layers of a web application.*

* [Apache Tapestry](https://tapestry.apache.org/) - Component-oriented framework for creating dynamic, robust, highly scalable web applications.
* [Apache Wicket](https://wicket.apache.org/) - Component-based web application framework similar to Tapestry, with a stateful GUI.
* [Blade](https://github.com/biezhi/blade) - Lightweight, modular framework that aims to be elegant and simple.
* [Bootique](http://bootique.io/) - Minimally opinionated framework for runnable apps.
* [Firefly](http://www.fireflysource.com/) - Asynchronous framework for rapid development of high-performance web application.
* [Grails](https://grails.org/) - Groovy framework that provides a highly productive environment by favoring convention over configuration, no XML and support for mixins.
* [Jooby](http://jooby.org) - Scalable, fast and modular micro-framework that offers multiple programming models.
* [Ninja](http://www.ninjaframework.org/) - Full-stack web framework.
* [Pippo](http://www.pippo.ro/) - Small, highly modularized, Sinatra-like framework.
* [Play](https://www.playframework.com/) - Built on Akka, it provides predictable and minimal resource consumption (CPU, memory, threads) for highly-scalable applications in Java and Scala.
* [PrimeFaces](https://primefaces.org/) - JSF framework with both free and commercial/support versions and frontend components.
* [Ratpack](https://ratpack.io/) - Set of libraries that facilitate fast, efficient, evolvable and well-tested HTTP applications.
* [Takes](https://github.com/yegor256/takes) - Opinionated web framework which is build around the concepts of True Object-Oriented Programming and immutablity.
* [Vaadin](https://vaadin.com/home) - Event-driven framework build on top of GWT. Uses server-side architecture with Ajax on the client side.

# Resources

## Awesome Lists

*Awesome lists related to the Java & JVM ecosystem.*

* [Awesome Gradle Plugins](https://github.com/ksoichiro/awesome-gradle)
* [AwesomeJavaFX](https://github.com/mhrimaz/AwesomeJavaFX)
* [Awesome JVM](https://github.com/deephacks/awesome-jvm)
* [Awesome Microservices](https://github.com/mfornos/awesome-microservices)
* [Awesome REST](https://github.com/marmelab/awesome-rest)
* [Awesome Selenium](https://github.com/christian-bromann/awesome-selenium)
* [ciandcd](https://github.com/ciandcd/awesome-ciandcd)
* [Useful Java Links](https://github.com/Vedenin/useful-java-links)

## Communities

*Active discussions.*

* [r/java](https://www.reddit.com/r/java) - Subreddit for the Java community.
* [stackoverflow](https://stackoverflow.com/questions/tagged/java) - Question/answer platform.
* [VirtualJUG](https://virtualjug.com/) - Virtual Java User Group.

## Frontends

*Websites that provide a frontend for this list. Please note, there won't be an official website. We don't associate with a particular website and everybody is allowed to create one.*

* [java.libhunt.com](https://java.libhunt.com/)

## Influential Books

*Books that made a big impact and are still worth reading.*

* [Core Java Volume I--Fundamentals](https://www.amazon.com/Core-Java-I-Fundamentals-10th/dp/0134177304)
* [Core Java, Volume II--Advanced Features](https://www.amazon.com/Core-Java-II-Advanced-Features-10th/dp/0134177290)
* [Effective Java (2nd Edition)](https://www.amazon.com/Effective-Java-Edition-Joshua-Bloch/dp/0321356683)
* [Java Concurrency in Practice](https://www.amazon.com/Java-Concurrency-Practice-Brian-Goetz/dp/0321349601)
* [Thinking in Java](https://www.amazon.com/Thinking-Java-Edition-Bruce-Eckel/dp/0131872486)

## Podcasts and Screencasts

*Something to look at or listen to while programming.*

* [Java Off Heap](http://www.javaoffheap.com/)
* [Marco Behler's Screencasts](https://www.marcobehler.com/series) - Screencasts about modern Java development.
* [The Java Council](https://virtualjug.com/podcast/)
* [The Java Posse](http://www.javaposse.com/) - Discontinued as of 02/2015.

## Twitter

*Active accounts to follow. Descriptions from Twitter.*

* [Adam Bien](https://twitter.com/AdamBien/) - Freelance author, JavaOne Rockstar speaker, consultant, Java Champion.
* [Aleksey Shipilëv](https://twitter.com/shipilev) - Performance geek, benchmarking czar, concurrency bug hunter.
* [Antonio Goncalves](https://twitter.com/agoncal/) - Java Champion, JUG Leader, Devoxx France, Java EE 6/7, JCP, Author.
* [Arun Gupta](https://twitter.com/arungupta/) - Java Champion, JavaOne Rockstar, JUG Leader, Devoxx4Kids-er, VP of Developer Advocacy at Couchbase.
* [Brian Goetz](https://twitter.com/BrianGoetz) - Java Language Architect at Oracle.
* [Bruno Borges](https://twitter.com/brunoborges) - Product Manager/Java Jock at Oracle.
* [Chris Richardson](https://twitter.com/crichardson) - Software architect, consultant, and serial entrepreneur, Java Champion, JavaOne Rock Star, *POJOs in Action* author.
* [Ed Burns](https://twitter.com/edburns) - Consulting Member of the Technical Staff at Oracle.
* [Eugen Paraschiv](https://twitter.com/baeldung) - Author of the Spring Security Course.
* [Heinz Kabutz](https://twitter.com/heinzkabutz) - Java Champion, speaker, author of The Java Specialists' Newsletter, concurrency performance expert.
* [Holly Cummins](https://twitter.com/holly_cummins) - Technical Lead of IBM London's Bluemix Garage, Java Champion, developer, author, JavaOne rockstar.
* [James Weaver](https://twitter.com/JavaFXpert) - Java/JavaFX/IoT developer, author and speaker.
* [Java EE](https://twitter.com/Java_EE/) - Official Java EE Twitter account.
* [Java Magazine](https://twitter.com/Oraclejavamag) - Official Java Magazine account.
* [Java](https://twitter.com/java/) - Official Java Twitter account.
* [Javin Paul](https://twitter.com/javinpaul) - Well-known Java blogger.
* [Josh Long](https://twitter.com/starbuxman) - Spring Advocate at Pivotal, author of O'Reilly's *Cloud Native Java* and *Building Microservices with Spring Boot*, JavaOne Rock Star.
* [Lukas Eder](https://twitter.com/lukaseder) - Java Champion, speaker, JUG.ch co-leader, Founder and CEO Data Geekery (jOOQ).
* [Mario Fusco](https://twitter.com/mariofusco) - RedHatter, JUG coordinator, frequent speaker and author.
* [Mark Heckler](https://twitter.com/MkHeck) - Pivotal Principal Technologist and Developer Advocate, conference speaker, published author, and Java Champion, focusing on Internet of Things and the cloud.
* [Mark Reinhold](https://twitter.com/mreinhold) - Chief Architect, Java Platform Group, Oracle.
* [Markus Eisele](https://twitter.com/myfear) - Java EE evangelist, Red Hat.
* [Martijn Verburg](https://twitter.com/karianna) - London JUG co-leader, speaker, author, Java Champion and much more.
* [Martin Thompson](https://twitter.com/mjpt777) - Pasty faced performance gangster.
* [Monica Beckwith](https://twitter.com/mon_beck) - Performance consultant, JavaOne Rock Star.
* [OpenJDK](https://twitter.com/OpenJDK) - Official OpenJDK account.
* [Peter Lawrey](https://twitter.com/PeterLawrey) - Peter Lawrey, Java performance expert.
* [Randy Shoup](https://twitter.com/randyshoup) - Stitch Fix VP Engineering, speaker, JavaOne Rock Star.
* [Reza Rahman](https://twitter.com/reza_rahman) - Java EE/GlassFish/WebLogic evangelist, author, speaker, open source hacker.
* [Simon Maple](https://twitter.com/sjmaple) - Java Champion, VirtualJUG founder, LJC leader, RebelLabs author.
* [Stephen Colebourne](https://twitter.com/jodastephen) - Java Champion, speaker.
* [Trisha Gee](https://twitter.com/trisha_gee) - Java Champion and speaker.
* [Venkat Subramaniam](https://twitter.com/venkat_s) - Author, University of Houston professor, MicroSoft MVP award recipient, JavaOne Rock Star, Java Champion.

## Websites

*Sites to read.*

* [Google Java Style](https://google.github.io/styleguide/javaguide.html)
* [InfoQ](https://www.infoq.com/)
* [Java Algorithms and Clients](https://algs4.cs.princeton.edu/code/)
* [Java, SQL, and jOOQ](https://blog.jooq.org/)
* [Java.net](https://community.oracle.com/community/java)
* [Javalobby](https://dzone.com/java-jdk-development-tutorials-tools-news)
* [JavaWorld](https://www.javaworld.com/)
* [JAXenter](https://jaxenter.com/)
* [RebelLabs](https://zeroturnaround.com/rebellabs/)
* [The Takipi Blog](http://blog.takipi.com/)
* [TheServerSide.com](http://www.theserverside.com/)
* [Vanilla Java](https://vanilla-java.github.io/)
* [Voxxed](https://www.voxxed.com/)

# Contributing

Contributions are very welcome!

Please have a look at the [CONTRIBUTING](https://github.com/akullpp/awesome-java/blob/master/CONTRIBUTING.md) guidelines.

[c]: https://cdn.rawgit.com/akullpp/23246ca832bda82bb505230bf3538e2a/raw/d9bcdb769bf025292f9c6bc1290f01f1fcd1f864/commercial.svg