- [dOOv](https://github.com/doov-io/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](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.
- [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.
- [Buck](https://github.com/facebook/buck) - Encourages the creation of small, reusable modules consisting of code and resources.
- [Gradle](https://gradle.org) - Incremental builds programmed via Groovy instead of declaring XML. Works well with Maven's dependency management.
- [Perses](https://github.com/nicolasmanic/perses) - Dynamically injects failure/latency at the bytecode level according to principles of chaos engineering.
- [picocli](http://picocli.info) - ANSI colors and styles in usage help with annotation-based POSIX/GNU/any syntax, subcommands, strong typing for both options and positional args.
- [Text-IO](https://github.com/beryx/text-io) - Aids the creation of full console-based applications.
- [Lanterna](https://github.com/mabe02/lanterna) - Easy console text-GUI library, similar to curses.
- [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.
- [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.
- [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.
- [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.
- [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.
- [HyperMinHash-java](https://github.com/LiveRamp/HyperMinHash-java) - Probabilistic data structure for computing union, intersection, and set cardinality in loglog space.
- [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.
- [Manifold](https://manifold.systems) - Re-energizes Java with powerful features like type-safe metaprogramming, structural typing and extension methods.
- [SneakyThrow](https://github.com/rainerhahnekamp/sneakythrow) - Ignores checked exceptions without bytecode manipulation. Can also be used inside Java 8 stream operations.
- [Apache Geode](https://geode.apache.org) - In-memory data management system that provides reliable asynchronous event notifications and guaranteed message delivery.
- [Apache ZooKeeper](https://zookeeper.apache.org) - Coordination service with distributed configuration, synchronization, and naming registry for large distributed systems.
- [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.
- [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.
- [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.
- [zerocell](https://github.com/creditdatamw/zerocell) - Annotation-based API for reading data from Excel sheets into POJOs with focus on reduced overhead.
- [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.
- [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.
- [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.
- [Visual Studio Code](https://code.visualstudio.com/docs/languages/java) - Provides Java support for lightweight projects with a simple, modern workflow by using extensions from the internal marketplace.
- [image-comparison](https://github.com/romankh3/image-comparison) - Java Library that compares 2 images with the same sizes and shows the differences visually by drawing rectangles. Some parts of the image can be excluded from the comparison. Can be used for automation qa tests.
- [DSL-JSON](https://github.com/ngs-doo/dsl-json) - JSON library with advanced compile time databinding.
- [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-modules-java8](https://github.com/FasterXML/jackson-modules-java8) - Set of Jackson modules for Java 8 datatypes and features.
- [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.
- [OpenJ9](https://github.com/eclipse/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.
- [Open JDK](https://openjdk.java.net) - Open JDK distributed by Oracle.
- [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.
- [FizzBuzz Enterprise Edition](https://github.com/EnterpriseQualityCoding/FizzBuzzEnterpriseEdition) - No-nonsense implementation of FizzBuzz made by serious businessmen for serious business purposes.
- [J2ObjC](https://github.com/google/j2objc) - Java-to-Objective-C translator for porting Android libraries to iOS.
- [Maven Wrapper](https://github.com/takari/maven-wrapper) - Analogue of Gradle Wrapper for Maven, allows building projects without installing maven.
- [Membrane Service Proxy](https://github.com/membrane/service-proxy) - An open-source, reverse-proxy framework written in Java.
- [MinimalFTP](https://github.com/Guichaguri/MinimalFTP) - Lightweight, small and customizable FTP server.
- [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.
- [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.
- [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.
- [OctoLinker](https://github.com/OctoLinker/browser-extension) - Browser extension which allows to navigate through code on GitHub more efficiently.
- [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.
- [Helidon](https://helidon.io) - Two-style approach for writing microservices: Functional-reactive and as an implementation of [MicroProfile](https://microprofile.io).
- [Automon](https://github.com/stevensouza/automon) - Combines the power of AOP with monitoring and/or logging tools.
- [BugSnag ![c]](https://www.bugsnag.com) - Exception and error monitoring with an integration of several third party tools for a better workflow and a free hobbyist tier.
- [Failsafe Actuator](https://github.com/zalando-incubator/failsafe-actuator) - Out of the box monitoring of Failsafe Circuit Breaker in Spring-Boot environment.
- [inspectIT](http://www.inspectit.rocks) - Captures detailed run-time information via hooks that can be changed on the fly. It supports tracing over multiple systems via the OpenTracing API and can correlate the data with end user monitoring.
- [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.
- [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.
- [zipkin](https://zipkin.io) - Distributed tracing system which gathers timing data needed to troubleshoot latency problems in microservice architectures.
- [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).
- [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.
- [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.
- [sshj](https://github.com/hierynomus/sshj) - Programatically use SSH, SCP or SFTP.
- [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.
- [Doma 2](https://doma.readthedocs.io) - 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.
- [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.
- [Convert](http://commons.apache.org/sandbox/commons-convert) - Commons-Convert aims to provide a single library dedicated to the task of converting an object of one type to another.
- [Functor](http://commons.apache.org/proper/commons-functor) - A functor is a function that can be manipulated as an object, or an object representing a single, generic function.
- [Graph](http://commons.apache.org/sandbox/commons-graph) - A general purpose Graph APIs and algorithms.
- [I18n](http://commons.apache.org/sandbox/commons-i18n) - Adds the feature of localized message bundles that consist of one or many localized texts that belong together.
- [Id](http://commons.apache.org/sandbox/commons-id) - Id is a component used to generate identifiers.
- [Monitoring](http://commons.apache.org/sandbox/commons-monitoring) - Monitoring aims to provide a simple but extensible monitoring solution for Java applications.
- [Nabla](http://commons.apache.org/sandbox/commons-nabla) - Nabla provides automatic differentiation classes that can generate derivative of any function implemented in the Java language.
- [OpenPGP](http://commons.apache.org/sandbox/commons-openpgp) - Interface to signing and verifying data using OpenPGP.
- [Performance](http://commons.apache.org/sandbox/commons-performance) - A small framework for microbenchmark clients, with implementations for Commons DBCP and Pool.
- [Pipeline](http://commons.apache.org/sandbox/commons-pipeline) - Provides a set of pipeline utilities designed around work queues that run in parallel to sequentially process data objects.
- [SCXML](http://commons.apache.org/proper/commons-scxml) - An implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine.
- [Validator](http://commons.apache.org/proper/commons-validator) - Framework to define validators and validation rules in an xml file.
- [VFS](http://commons.apache.org/proper/commons-vfs) - Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.
- [Weaver](http://commons.apache.org/proper/commons-weaver) - Provides an easy way to enhance (weave) compiled bytecode.
- [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.
- [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.
- [RxJava](https://github.com/ReactiveX/RxJava) - Allows for composing asynchronous and event-based programs using observable sequences.
- [Dropwizard](https://dropwizard.github.io/dropwizard) - Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.
- [javalin](https://javalin.io) - Javalin is just a few thousand lines of code on top of Jetty, which means its performance is almost equivalent to pure Jetty.
- [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.
- [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.
- [Swagger](https://swagger.io) - Standard, language-agnostic interface to REST APIs.
- [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.
- [Orson-Charts](https://github.com/jfree/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.
- [Tablesaw](https://github.com/lwhite1/tablesaw) - Includes a data-frame, an embedded column store, and hundreds of methods to transform, summarize, or filter data.
- [Elasticsearch](https://www.elastic.co) - Distributed, multitenant-capable, full-text search engine with a RESTful web interface and schema-free JSON documents.
- [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.
- [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.
- [FlatBuffers](https://github.com/google/flatbuffers) - Memory-efficient serialization library that can access serialized data without unpacking and parsing it.
- [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.
- [Pebble](https://pebbletemplates.io) - Inspired by Twig and separates itself with its inheritance feature and its easy-to-read syntax. It ships with built-in autoescaping for security and it includes integrated support for internationalization.
- [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.
- [Serenity BDD](https://www.thucydides.info) - Automated Acceptance testing and reporting library that works with Cucumber, JBehave and JUnit to make it easier to write high quality executable specifications.
- [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.
- [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.
- [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.
- [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.
- [fswatch](https://github.com/vorburger/ch.vorburger.fswatch) - Micro library to watch for directory file system changes, simplifying java.nio.file.WatchService
- [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.
- [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.
- [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.
- [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 built around the concepts of True Object-Oriented Programming and immutability.
- [Vaadin Flow](https://vaadin.com/flow) - Event-driven framework that uses standard web components. Server-side architecture with Ajax on the client side.
*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.*
- [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.
- [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.
- [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.
