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Awesome Java Awesome

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

Ancients

In existence since the beginning of time and which will continue being used long after the hype has waned.

  • Apache Ant - Build process management with XML.
  • Apache Hadoop - Storage and large-scale processing of data-sets on clusters of commodity hardware.
  • Apache OpenNLP - Toolkit for common tasks like tokenization.
  • Apache Velocity - Templates for HTML pages, emails or source code generation in general.
  • FreeMarker - General templating engine without any heavyweight or opinionated dependencies.
  • GlassFish - Application server and reference implementation for Java EE sponsored by Oracle.
  • GWT - Toolbox which includes a Java-to-JavaScript compiler for client-side code, XML parser, API for RPC, JUnit integration, internationalization support and widgets for the GUI.
  • Hamcrest - Matchers that can be combined to create flexible expressions of intent.
  • HornetQ - Clear, concise, modular and made to be embedded.
  • Hudson - Continuous integration server still in active development.
  • Java Modeling Language (JML) - Behavioral interface specification language that can be used to specify the behavior of code modules. It combines the design by contract approach of Eiffel and 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 - More specific and slightly easier to learn. Has syntactic lookahead.
  • JavaServer Faces - Oracle's open-source implementation of the JSF standard, Mojarra.
  • JavaServer Pages - Common templating for websites with custom tag libraries.
  • JUnit - Common testing framework.
  • Launch4j - Wraps JARs in lightweight and native Windows executables.
  • Quartz - Open-source job scheduler library with Apache 2.0 license.
  • TestNG - Testing framework.
  • Trove - Primitive collections.

Bean Mapping

Frameworks that ease bean mapping.

  • Dozer - Mapper that copies data from one object to another, using annotations, API or XML configuration.
  • JMapper - Using byte code manipulation for lightning fast mapping. Supporting annotations, API or XML configuration.
  • MapStruct - Code generator which simplifies mappings between different bean types, based on a convention over configuration approach.
  • ModelMapper - ModelMapper is an intelligent object mapping library that automatically maps objects to each other.
  • Orika - Orika is a Java Bean mapping framework that recursively copies (among other capabilities) data from one object to another.
  • Selma - Stupid Simple Statically Linked Mapper. Selma is an Annotation Processor Based bean mapper.

Build

Tools which handle the build cycle and dependencies of an application.

  • Apache Maven - Declarative build and dependency management which favors convention over configuration. It might be preferable to Apache Ant which uses a rather procedural approach and can be difficult to maintain.
  • Bazel - Build tool from Google that builds code quickly and reliably.
  • Gradle - Incremental builds which are programmed via Groovy instead of declaring XML. Works well with Maven's dependency management.

Bytecode Manipulation

Libraries to manipulate bytecode programmatically.

  • ASM - All purpose, low level, bytecode manipulation and analysis.
  • Byte Buddy - Further simplifies bytecode generation with a fluent API.
  • Byteman - Manipulate bytecode at runtime via DSL (rules) mainly for testing/troubleshooting.
  • cglib - Bytecode generation library.
  • Javassist - Tries to simplify the editing of bytecode.

Caching

Libraries which provide caching facilities.

  • Caffeine - High performance, near optimal caching library.
  • Ehcache - Distributed general purpose cache.

Cluster Management

Frameworks which can dynamically manage applications inside of a cluster.

  • Apache Aurora - Apache Aurora is a Mesos framework for long-running services and cron jobs.
  • Apache Mesos - Abstracts CPU, memory, storage, and other compute resources away from machines.
  • Singularity - Singularity is a 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 - Static analysis of coding conventions and standards.
  • Codacy - Continuous static analysis, code coverage, and software metrics to automate code reviews.
  • Error Prone - Catches common programming mistakes as compile-time errors.
  • FindBugs - Static analysis of bytecode to find potential bugs.
  • Infer - Tool to produce a list of potential bugs.
  • jQAssistant - Static code analysis with Neo4J-based query language.
  • PMD - Source code analysis for finding bad coding practices.
  • SonarQube - Integrates other analysis components via plugins and provides an overview of the metrics over time.
  • Spoon - Library for analyzing and transforming Java source code.

Code Coverage

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

  • Clover - Proprietary code coverage tool by Atlassian that relies on source-code instrumentation, instead of bytecode instrumentation.
  • Cobertura - Relies on offline (or static) bytecode instrumentation and class loading to collect code coverage metrics; GPLv2 licensed.
  • JaCoCo - Framework that enables collection of code coverage metrics, using both offline and runtime bytecode instrumentation; prominently used by EclEmma, the Eclipse code-coverage plugin.

Code Generators

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

  • ADT4J - JSR-269 code generator for algebraic data types.
  • Auto - Generates factory, service, and value classes.
  • FreeBuilder - Automatic generation of the Builder pattern.
  • Immutables - Annotation processors to generate simple, safe and consistent value objects.
  • JHipster - Yeoman source code generator for Spring Boot and AngularJS.
  • Joda-Beans - Small framework that adds queryable properties to Java, enhancing JavaBeans.
  • Lombok - Code generator which aims to reduce verbosity.

Command-line Argument Parsers

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

  • Airline - Annotation-based framework for parsing Git like command line arguments.
  • args4j - Small library to parse command like arguments similar to javac.
  • JCommander - Command line arguments parsing framework with custom types and validation via implementing interfaces.
  • JOpt Simple - Simple parser that uses the POSIX getopt() and GNU getopt_long() syntaxes. Does not use annotations, uses a fluent API instead.

Compiler-compiler

Frameworks that help to create parsers, interpreters or compilers.

  • ANTLR - Complex full-featured framework for top-down parsing.
  • JFlex - A lexical analyzer generator.

Configuration

Libraries that provide external configuration.

  • config - Configuration library for JVM languages.
  • ini4j - Provides an API for handling Windows' INI files.
  • owner - Reduces boilerplate of properties.
  • KAConf - Annotation-based configuration system for Java and Kotlin.

Constraint Satisfaction Problem Solver

Libraries that help on implementing optimization and satisfiability problems.

  • Choco - Off-the-shelf constraint satisfaction problem solver, which uses constraint programming techniques.
  • JaCoP - Includes an interface for the FlatZinc language, enabling it to execute MiniZinc models.
  • OptaPlanner - Business planning and resource scheduling optimization solver.

Continuous Integration

Tools which support continuously building, testing and releasing applications.

  • Bamboo c - Atlassian's solution with good integration of their other products. You can either apply for an open-source license or buy it.
  • Concourse - Provides dockerized pipeline with configuration that can be saved in version control.
  • fabric8 - Integration platform for containers.
  • Go - ThoughtWork's open-source solution.
  • Jenkins - Provides server-based deployment services.
  • Semaphore - Hosted CI/CD service, free for open-source and 100 private builds with native Docker support.
  • TeamCity - JetBrain's CI solution with a free version.
  • Travis - Hosted service often used for open-source projects.

CSV

Frameworks and libraries that simplify reading/writing CSV data.

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

Database

Everything which simplifies interactions with the database.

  • Apache Hive - Data warehouse infrastructure built on top of Hadoop.
  • Apache Phoenix - High performance relational database layer over HBase for low latency applications.
  • Chronicle Map - Efficient in-memory (opt. persisted to disk) off-heap key-value store.
  • eXist - A NoSQL document database and application platform.
  • FlexyPool - Brings metrics and failover strategies to the most common connection pooling solutions.
  • Flyway - Simple database migration tool.
  • H2 - Small SQL Database notable for its in-memory functionality.
  • HikariCP - High performance JDBC connection pool.
  • JDBI - Convenient abstraction of JDBC.
  • Jedis - A small client for interaction with redis, with methods for commands.
  • jetcd - A client library for etcd.
  • jOOQ - Generates typesafe code based on SQL schema.
  • Liquibase - Database-independent library for tracking, managing and applying database schema changes.
  • MapDB - Embedded database engine that provides concurrent collections backed on disk or in off-heap memory.
  • MariaDB4j - Launcher for MariaDB which requires no installation or external dependencies.
  • Presto - Distributed SQL query engine for big data.
  • Querydsl - Typesafe unified queries.
  • Realm - Mobile database to run directly inside phones, tablets or wearables.
  • Redisson - Allows for distributed and scalable data structures on top of a Redis server.
  • Speedment - Database access library that utilizes the Java 8 Stream API for querying.
  • sql2o - Thin JDBC wrapper that simplifies database access and provides simple mapping of ResultSets to POJOs.
  • Vibur DBCP - JDBC connection pool library which offers advanced performance monitoring capabilities.

Data structures

Efficient and specific data structures.

  • Apache Avro - Data interchange format featuring among others: dynamic typing, untagged data, absence of manually assigned IDs.
  • Apache Orc - Fast and efficient columnar storage format for hadoop based workloads.
  • Apache Parquet - Columnar storage format based on assembly algorithms from the Dremel paper by Google.
  • Apache Thrift - Data interchange format that originated at Facebook.
  • Persistent Collection - Persistent and immutable analogue of the Java Collections Framework.
  • Protobuf - Google's data interchange format.
  • SBE - Simple Binary Encoding, one of the fastest message formats around.
  • Wire - Clean, lightweight protocol buffers.

Date and Time

Libraries related to handling date and time.

  • Almanac Converter - Simple conversion between different calendar systems.
  • iCal4j - Parsing and building iCalendar RFC 5545 data models.
  • Joda-Time - De facto standard date/time-library before Java 8.
  • ThreeTenBP - Port of JSR 310 (java.time package) by the author of Joda-Time.
  • Time4J - Advanced date and time library.

Dependency Injection

Libraries that help to realize the Inversion of Control paradigm.

  • Apache DeltaSpike - CDI extension framework.
  • Dagger2 - Compile-time injection framework without reflection.
  • Guice - Lightweight but powerful framework that completes Dagger.
  • HK2 - Light-weight and dynamic dependency injection framework.

Development

Augmentation of the development process at a fundamental level.

  • AspectJ - Seamless aspect-oriented programming extension.
  • DCEVM - Modification of the JVM that allows unlimited redefinition of loaded classes at runtime.
  • Faux Pas - Library that simplifies error handling by circumventing the issue that none of the functional interfaces in the Java Runtime is allowed by default to throw checked exceptions.
  • HotswapAgent - Unlimited runtime class and resource redefinition.
  • JavaParser - Parse, modify and generate Java code.
  • JavaSymbolSolver - A symbol solver for Java.
  • JRebel c - Instantly reloads code and configuration changes without redeploys.
  • Spring Loaded - Class reloading agent.

Distributed Applications

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

  • Akka - Toolkit and runtime for building concurrent, distributed, and fault tolerant event-driven applications.
  • Apache Storm - Realtime computation system.
  • Apache ZooKeeper - Coordination service with distributed configuration, synchronization, and naming registry for large distributed systems.
  • Atomix - Fault-tolerant distributed coordination framework.
  • Axon Framework - Framework for creating CQRS applications.
  • Copycat - Fault-tolerant state machine replication framework.
  • Hazelcast c - Highly scalable in-memory datagrid with a free open-source version.
  • Hystrix - Provides latency and fault tolerance.
  • JGroups - Toolkit for reliable messaging and creating clusters.
  • Orbit - Virtual Actors, adding another level of abstraction to traditional actors.
  • Quasar - Lightweight threads and actors for the JVM.

Distributed Databases

Databases in a distributed system that appear to applications as a single data source.

  • Apache Cassandra - Column-oriented and providing high availability with no single point of failure.
  • Apache HBase - Hadoop database for big data.
  • Druid - Real-time and historical OLAP data store that excel at aggregation and approximation queries.
  • Infinispan - Highly concurrent key/value datastore used for caching.
  • OpenTSDB - Scalable and distributed time series database written on top of Apache HBase.
  • OrientDB - Embeddable distributed database written on top of Hazelcast.

Distribution

Tools which handle the distribution of applications in native formats.

  • Bintray c - Version control for binaries which handles the publishing. Can also be used with Maven or Gradle and has a free plan for open-source software or several business plans.
  • Boxfuse - Deployment of JVM application to AWS using the principles of Immutable Infrastructure.
  • Capsule - Simple and powerful packaging and deployment. A fat JAR on steroids or a "Docker for Java" that supports JVM-optimized containers.
  • Central Repository - 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 - Setup authoring tool for cross-platform deployments.
  • JitPack - Easy to use package repository for GitHub. Builds Maven/Gradle projects on demand and publishes ready-to-use packages.
  • Nexus c - Binary management with proxy and caching capabilities.
  • packr - Packs JARs, assets and the JVM for native distribution on Windows, Linux and Mac OS X.
  • really-executable-jars-maven-plugin - Maven plugin for making self-executing JARs.

Document Processing

Libraries that assist with processing office document formats.

  • Apache POI - Supports OOXML (XLSX, DOCX, PPTX) as well as OLE2 (XLS, DOC or PPT).
  • documents4j - API for document format conversion using third-party converters such as MS Word.
  • docx4j - Creating and manipulating Microsoft Open XML files.

Formal Verification

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

  • CATG - Concolic unit testing engine. Automatically generates unit tests using formal methods.
  • Checker Framework - Pluggable type systems. Includes nullness types, physical units, immutability types and more.
  • Daikon - Daikon detects likely program invariants and can generate JML specs based on those invariats.
  • Java Path Finder (JPF) - JVM formal verification tool containing a model checker and more. Created by NASA.
  • JMLOK 2.0 - Detects nonconformances between code and JML specification through the feedback-directed random tests generation, and suggests a likely cause for each nonconformance detected.
  • KeY - The KeY System is a 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 - 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 - Monad and stream utilities, comprehensions, pattern matching, functional extensions for all JDK collections, future streams, trampolines and much more.
  • derive4j - Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching, morphisms.
  • Fugue - Functional extensions to Guava.
  • Functional Java - Implements numerous basic and advanced programming abstractions that assist composition-oriented development.
  • Javaslang - Functional component library that provides persistent data types and functional control structures.
  • jOOλ - Extension to Java 8 which aims to fix gaps in lambda, providing numerous missing types and a rich set of sequential Stream API additions.
  • protonpack - Collection of stream utilities.
  • StreamEx - Enhancing Java 8 Streams.

Game Development

Frameworks that support the development of games.

  • jMonkeyEngine - Game engine for modern 3D development.
  • libGDX - All-round cross-platform, high-level framework.
  • LWJGL - Robust framework that abstracts libraries like OpenGL/CL/AL.

Geospatial

Libraries for working with geospatial data and algorithms.

  • Apache SIS - Library for developing geospatial applications.
  • Geo - GeoHash utilities in Java.
  • Geotoolkit.org - Library for developing geospatial applications. Built on top of the Apache SIS project.
  • GeoTools - Library that provides tools for geospatial data.
  • GraphHopper - Road routing engine. Used as Java library or standalone web service.
  • H2GIS - A spatial extension of the H2 database.
  • Jgeohash - Library that can assist Java developers in using the GeoHash algorithm.
  • Mapsforge - Software for the rendering of maps based on OpenStreetMap data.
  • Spatial4j - General purpose spatial/geospatial ASL licensed open-source Java library.

GUI

Libraries to create modern graphical user interfaces.

  • JavaFX - The successor of Swing.
  • Scene Builder - Visual layout tool for JavaFX applications.
  • SWT - The Standard Widget Toolkit (SWT) is a graphical widget toolkit for use with the Java platform.

High Performance

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

  • Agrona - Data structures and utility methods that are common in high-performance applications.
  • Disruptor - Inter-thread messaging library.
  • Eclipse Collections - Collections framework inspired by Smalltalk.
  • fastutil - Fast and compact type-specific collections.
  • HPPC - Primitive collections.
  • JCTools - Concurrency tools currently missing from the JDK.
  • Koloboke - Hash sets and hash maps.

Hypermedia Types

Libraries that handle serialization to hypermedia types.

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

IDE

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

  • Eclipse - Established, open-souce project with support for lots of plugins and languages.
  • IntelliJ IDEA c - Supports a lot of JVM languages and provides good options for Android development. The commercial edition targets the enterprise sector.
  • NetBeans - 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 - Simple and efficient hardware-accelerated image-scaling library implemented in pure Java 2D.
  • Tess4J - A JNA wrapper for Tesseract OCR API.
  • Thumbnailator - Thumbnailator is a high-quality thumbnail generation library for Java.
  • TwelveMonkeys - Collection of plugins which extend the number of supported image file formats.
  • ZXing - Multi-format 1D/2D barcode image processing library.

JSON

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

  • Genson - Powerful and easy to use Java to JSON conversion library.
  • Gson - Serializes objects to JSON and vice versa. Good performance with on-the-fly usage.
  • Jackson-datatype-money - Open-source Jackson module to support JSON serialization and deserialization of JavaMoney data types.
  • Jackson - Similar to GSON but has performance gains if you need to instantiate the library more often.
  • JSON-io - Convert Java to JSON. Convert JSON to Java. Pretty print JSON. Java JSON serializer.
  • jsoniter - Fast and flexible library with iterator and lazy parsing API.
  • LoganSquare - JSON parsing and serializing library based on Jackson's streaming API. Outperforms GSON & Jackson's library.

JSON Processing

Libraries for processing data in JSON format.

  • fastjson - Very fast processor with no additional dependencies and full data binding.
  • Jolt - JSON to JSON transformation tool.
  • JsonPath - Extract data from JSON using XPATH like syntax.
  • JsonSurfer - Streaming JsonPath processor dedicated to processing big and complicated JSON data.

JVM and JDK

Current implementations of the JVM/JDK.

  • Avian - JVM with both a JIT & AOT modes. Includes an iOS port.
  • JDK 9 - Early access releases of JDK 9.
  • OpenJDK - Open-source implementation for Linux.
  • ParparVM - VM with non-blocking concurrent GC for iOS.
  • Zulu OpenJDK 9 - Early access OpenJDK 9 builds for Windows, Linux, and Mac OS X.
  • Zulu OpenJDK - OpenJDK builds for Windows, Linux, and Mac OS X through Java 8.

Logging

Libraries that log the behavior of an application.

  • Apache Log4j 2 - Complete rewrite with a powerful plugin and configuration architecture.
  • Graylog - Open-source aggregator suited for extended role and permission management.
  • Kibana - Analyzes and visualizes log files. Some features require payment.
  • Logback - Robust logging library with interesting configuration options via Groovy.
  • Logbook - Extensible, open-source library for HTTP request and response logging.
  • Logstash - Tool for managing log files.
  • SLF4J - Abstraction layer which is to be used with an implementation.
  • tinylog - Lightweight logging framework with static logger class.
  • Tracer - Call tracing and log correlation in distributed systems.

Machine Learning

Tools that provide specific statistical algorithms which allow learning from data.

  • Apache Flink - Fast and reliable large-scale data processing engine.
  • Apache Mahout - Scalable algorithms focused on collaborative filtering, clustering and classification.
  • Apache Spark - Data analytics cluster computing framework.
  • DatumBox - Provides several algorithms and pre-trained models for natural language processing.
  • DeepDive - Creates structured information from unstructured data and integrates it into an existing database.
  • Deeplearning4j - Distributed and multi-threaded deep learning library.
  • H2O - Analytics engine for statistics over big data.
  • JSAT - Algorithms for pre-processing, classification, regression, and clustering with support for multi-threaded execution.
  • Oryx 2 - A framework for building real-time large scale machine learning applications, which also includes end-to-end applications for collaborative filtering, classification, regression, and clustering.
  • Smile - The Statistical Machine Intelligence and Learning Engine provides a set of machine learning algorithms and a visualization library.
  • Weka - Collection of algorithms for data mining tasks ranging from pre-processing to visualization.

Messaging

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

  • Aeron - Efficient reliable unicast and multicast message transport.
  • Apache ActiveMQ - Message broker that implements JMS and converts synchronous to asynchronous communication.
  • Apache Camel - Glues together different transport APIs via Enterprise Integration Patterns.
  • Apache Kafka - High-throughput distributed messaging system.
  • Hermes - Fast and reliable message broker built on top of Kafka.
  • JeroMQ - Implementation of ZeroMQ.
  • Nakadi - Provides a RESTful API on top of Kafka.
  • RocketMQ - A fast, reliable, and scalable distributed messaging platform.
  • Smack - Cross-platform XMPP client library.

Miscellaneous

Everything else.

  • Codename One - Cross platform solution for writing native mobile (iOS, Android, etc.)
  • CQEngine - Ultra-fast SQL-like queries on Java collections.
  • Design Patterns - Implementation and explanation of the most common design patterns.
  • Failsafe - Simple failure handling with retries and circuit breakers.
  • J2ObjC - Java to Objective-C translator for porting Android libraries to iOS.
  • jabba - Java Version Manager inspired by nvm.
  • javaslang-circuitbreaker - Functional fault tolerance library.
  • JavaX - Reinventing and extending Java with a focus on simplicity.
  • JBake - Static website generator.
  • Jimfs - In-memory file system.
  • Joda-Money - Basic currency and money classes and algorithms not provided by the JDK.
  • JPad - Snippet runner.
  • Lanterna - Easy console text GUI library similar to curses.
  • LightAdmin - Pluggable CRUD UI library for rapid application development.
  • Membrane Service Proxy - An open source, reverse proxy framework written in Java.
  • Modern Java - A Guide to Java 8 - Popular Java 8 guide.
  • Modernizer - Detect uses of legacy Java APIs.
  • OpenRefine - Tool for working with messy data: cleaning, transforming, extending it with web services and linking it to databases.
  • TypeTools - Tools for resolving generic types.

Microservice

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

  • Apollo - Libraries for writing composable microservices.
  • consul-api - Client for the Consul API a distributed, highly available and datacenter-aware registry/discovery service.
  • Eureka - REST based service registry for resilient load balancing and failover.
  • Lagom - Framework for creating microservice-based systems.
  • SnopEE - Discovery service for Java EE microservices.
  • restQL-core - Microservice query language that fetches information from multiple services.

Monitoring

Tools that monitor applications in production.

  • AppDynamics c - Performance monitor.
  • Glowroot - Open source Java APM.
  • JavaMelody - Performance monitoring and profiling.
  • jmxtrans - Tool to connect to multiple JVMs and to query them for their attributes via JMX. Its query language is based on JSON, which allows non-Java programmers to access the JVMs attributes. Likewise, this tool supports different output writes, including Graphite, Ganglia, StatsD, among others.
  • Jolokia - JMX over REST.
  • Kamon - Tool for monitoring applications running on the JVM.
  • Metrics - Expose metrics via JMX or HTTP and can send them to a database.
  • New Relic c - Performance monitor.
  • nudge4j - Remote developer console from the browser for Java 8 via bytecode injection.
  • OverOps c - In-Production error monitoring and debugging.
  • Pinpoint - Open source APM tool.
  • Prometheus - Provides a multi-dimensional data model, DSL, autonomous server nodes and much more.
  • SPM c - Performance monitor with distributing transaction tracing for JVM apps.
  • Stagemonitor - Open source performance monitoring and transaction tracing for JVM apps.

Native

For working with platform-specific native libraries.

  • JNA - Work with native libraries without writing JNI. Also provides interfaces to common system libraries.
  • JNR - Work with native libraries without writing JNI. Also provides interfaces to common system libraries. Same goals as JNA, but faster, and serves as the basis for the upcoming Project Panama.
  • JavaCPP - Provides efficient and easy access to native C++.

Natural Language Processing

Libraries that specialize on processing text.

  • CoreNLP - Stanford's CoreNLP provides a set of fundamental tools for tasks like tagging, named entity recognition, sentiment analysis and many more.
  • DKPro - A collection of re-usable NLP tools for linguistic pre-processing, machine learning, lexical resources, etc.
  • LingPipe - Toolkit for a variety of tasks ranging from POS tagging to sentiment analysis.

Networking

Libraries for network programming.

  • Async Http Client - Asynchronous HTTP and WebSocket client library.
  • Comsat - Integrates standard Java web-related APIs with Quasar fibers and actors.
  • Finagle - Extensible RPC system used to construct high-concurrency servers. It implements uniform client and server APIs for several protocols, and is protocol agnostic, which simplifies the implementation of new protocols.
  • Grizzly - NIO framework. Used as a network layer in Glassfish.
  • gRPC - RPC framework based on protobuf and HTTP/2.
  • MINA - Abstract event-driven async I/O API for network operations over TCP/IP and UDP/IP via Java NIO.
  • Netty - Framework for building high performance network applications.
  • Nifty - Implementation of Thrift clients and servers on Netty.
  • OkHttp - HTTP+SPDY client.
  • Riptide - Client-side response routing for Spring's RestTemplate.
  • Undertow - Web server providing both blocking and non-blocking API’s based on NIO. Used as a network layer in WildFly.
  • urnlib - Java library for representing, parsing and encoding URNs as in RFC 2141.

ORM

APIs which handle the persistence of objects.

  • Apache Cayenne - Provides clean, static API for data access. Also includes GUI Modeler for working with database mappings, DB reverse engineering and generation.
  • Ebean - Provides simple and fast data access.
  • EclipseLink - Supports a number of persistence standards: JPA, JAXB, JCA and SDO.
  • Hibernate - Robust and widely used with an active community.
  • MyBatis - Couples objects with stored procedures or SQL statements.

PaaS

Java platform as a service.

PDF

Everything that helps with the creation of PDF files.

Performance analysis

Tools for performance analysis, profiling and benchmarking.

  • fastThread c - Analyze and visualize thread dumps with a free cloud-based upload interface.
  • GCeasy c - Tool to analyze and visualize GC logs. It provides a free cloud-based upload interface.
  • honest-profiler - An low-overhead, bias-free sampling profiler.
  • jHiccup - Logs and records platform JVM stalls.
  • JITWatch - Analyze the JIT compiler optimisations made by the HotSpot JVM.
  • JMH - JMH is a Java harness for building, running, and analysing nano/micro/milli/macro benchmarks written in Java and other languages targeting the JVM.
  • JProfiler c - Profiler.
  • LatencyUtils - Utilities for latency measurement and reporting.
  • XRebel c - Profiler for web applications.
  • YourKit Java Profiler c - Profiler.

Platform

Frameworks that are suites of multiple libraries encompassing several categories.

  • CUBA Platform - High level framework for development of enterprise applications with rich web interface, based on Spring, EclipseLink and Vaadin.
  • Light-Java - A fast, lightweight and productive microservices framework with security built in.
  • Orienteer - Open source business application platform for rapid configuration/development of CRM, ERP, LMS and other applications.
  • Spring - Provides many packages ranging from dependency injection to aspect-oriented programming to security.

Reactive libraries

Libraries for developing reactive applications.

  • Reactive Streams - Provide a standard for asynchronous stream processing with non-blocking backpressure.
  • Reactor - Library for building reactive fast-data applications.
  • RxJava - Library for composing asynchronous and event-based programs using observable sequences from the JVM.
  • vert.x - Polyglot event-driven application framework.

REST Frameworks

Frameworks specifically for creating RESTful services.

  • Dropwizard - Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.
  • Feign - HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.
  • Jersey - JAX-RS reference implementation.
  • Microserver — A convenient extensible Microservices plugin system for Spring & Spring Boot, with over 30 plugins and growing, that supports both micro-monolith and pure microservices styles.
  • RAML - Modeling language to generate REST APIs with contract first.
  • Rapidoid - A simple, secure and extremely fast framework consisting of embedded HTTP server, GUI components and dependency injection.
  • rest.li - Framework for building robust, scalable RESTful architectures using type-safe 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 - Fully certified and portable implementation of the JAX-RS specification.
  • RestExpress - Thin wrapper on the JBoss Netty HTTP stack to provide scaling and performance.
  • Restlet Framework - Pioneering framework with powerful routing and filtering capabilities, unified client and server API.
  • Retrofit - Type-safe REST client.
  • Spark - Sinatra inspired framework.
  • Swagger - Swagger is a specification and complete framework implementation for describing, producing, consuming, and visualizing RESTful web services.

Science

Libraries for scientific computing, analysis and visualization.

  • DataMelt - Environment for scientific computation, data analysis and data visualization.
  • GraphStream - Library for modeling and analysis of dynamic graphs.
  • JGraphT - Graph library that provides mathematical graph-theory objects and algorithms.
  • JGraphX - Library for visualisation (mainly Swing) and interaction with node-edge graphs.
  • Erdos - Modular, light and easy graph theoretic framework.

Engines which index documents for search and analysis.

  • Apache Lucene - High-performance, full-featured cross-platform text search engine library.
  • Apache Solr - Enterprise search engine optimized for high volume traffic.
  • Elasticsearch - 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 - Performs authentication, authorization, cryptography and session management.
  • Bouncy Castle - All-purpose cryptographic library. JCA provider, wide range of functions from basic helpers to PGP/SMIME operations.
  • Cryptomator - Multiplatform transparent client-side encryption of files in the cloud.
  • Hdiv - Runtime application self-protection against OWASP Top 10 security risks such us Insecure Direct Object References, SQL injection, Cross-Site Scripting (XSS), Cross-Site Request Forgery (CSRF) and much more.
  • jjwt - Java JWT: JSON Web Token for Java and Android.
  • Keycloak - Integrated SSO and IDM for browser apps and RESTful web services.
  • Keyczar - Easy to use, yet safe encryption framework with key versioning.
  • Nbvcxz - Advanced password strength estimation.
  • OACC - Provides permission-based authorization services.
  • pac4j - Security engine.
  • PicketLink - Umbrella project for security and identity management.

Serialization

Libraries that handle serialization with high efficiency.

  • FlatBuffers - Memory efficient serialization library that can access serialized data without unpacking and parsing it.
  • FST - JDK compatible high performance object graph serialization.
  • Kryo - Fast and efficient object graph serialization framework.
  • MessagePack - Efficient binary serialization format.

Server

Servers which are specifically used to deploy applications.

  • Apache Tomcat - Robust all-round server for Servlet and JSP.
  • Apache TomEE - Tomcat plus Java EE.
  • Jetty - Lightweight, small server, often embedded in projects.
  • nanohttpd - Tiny, easily embeddable HTTP server.
  • WebSphere Liberty - Lightweight, modular server developed by IBM.
  • WildFly - Formerly known as JBoss and developed by Red Hat with extensive Java EE support.

Template Engine

Tools which substitute expressions in a template.

  • Handlebars.java - Logic-less and semantic Mustache templates.
  • Jtwig - Modular, configurable and fully tested template engine.
  • Thymeleaf - Aims to be a substitute for JSP and works for XML files in general.

Testing

Tools that test from model to the view.

  • Apache JMeter - Functional testing and performance measurements.
  • Arquillian - Integration and functional testing platform for Java EE containers.
  • AssertJ - Fluent assertions that improve readability.
  • Awaitility - DSL for synchronizing asynchronous operations.
  • Citrus - Integration testing framework with focus on client- and serverside messaging.
  • ConcurrentUnit - Toolkit for testing multi-threaded and asynchronous applications.
  • Cucumber - BDD testing framework.
  • Cukes-REST - A collection of Gherkin steps for REST-service testing using Cucumber.
  • Gatling - Load testing tool designed for ease of use, maintainability and high performance.
  • GreenMail - In-memory email server for integration testing. Supports SMTP, POP3 and IMAP including SSL.
  • J8Spec - J8Spec is a library that allows tests written in Java to follow the BDD style introduced by RSpec and Jasmine.
  • JSONAssert - Simplifies testing of JSON strings.
  • JBehave - Framework for Behavioural Driven Development.
  • [JFairy] (https://github.com/Codearte/jfairy) - Fake data generator.
  • JGiven - Developer-friendly BDD testing framework compatible with JUnit and TestNG.
  • JMockit - Mocks static, final methods and more.
  • junit-dataprovider - A TestNG like dataprovider runner for JUnit.
  • JUnitParams - Creation of readable and maintainable parametrised tests.
  • Lamdba Behave - Descriptive behavioural specification framework.
  • Mockito - Creation of test double objects in automated unit tests for the purpose of TDD or BDD.
  • MockServer - Allows mocking of systems that are integrated with HTTP/S.
  • Moco - Concise web services for stubs and mocks, Duke's Choice Award 2013.
  • PIT - Fast mutation-testing framework for evaluating fault-detection abilities of existing JUnit or TestNG test-suites.
  • pojo-tester - Automatically performs tests on basic POJO-methods.
  • PowerMock - Enables mocking of static methods, constructors, final classes and methods, private methods and removal of static initializers.
  • raml-tester - Tests if a request/response matches a given RAML definition.
  • REST Assured - Java DSL for easy testing for REST/HTTP services.
  • Selenide - Concise API around Selenium to write stable and readable UI tests.
  • Selenium - Portable software testing framework for web applications.
  • Spock - JUnit-compatible framework featuring an expressive Groovy-derived specification language.
  • TestContainers - Provides throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.
  • Truth - Google's assertion and proposition framework.
  • WireMock - Stubs and mocks web services.

Utility

Libraries which provide general utility functions.

  • Apache Commons - Provides different general purpose functions like configuration, validation, collections, file upload or XML processing.
  • CRaSH - Provides a shell into a JVM that's running CRaSH. Used by Spring Boot and others.
  • Dex - Java/JavaFX tool capable of powerful ETL and data visualization.
  • Embulk - Bulk data loader that helps data transfer between various databases, storages, file formats, and cloud services.
  • Gephi - Cross-platform for visualizing and manipulating large graph networks.
  • Guava - Collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and so forth.
  • JADE - Framework and environment for building and to debugging multi-agent systems.
  • JavaVerbalExpressions - A library that helps to construct difficult regular expressions.
  • minio-java - Provides simple APIs to access any Amazon S3 compatible object storage server.
  • Protégé - Provides an ontology editor and a framework to build knowledge-based systems.
  • Underscore-java - Port of Underscore.js functions.
  • JGit - A lightweight pure Java library implementing the Git version control system.

Web Crawling

Libraries that analyze the content of websites.

  • Apache Nutch - Highly extensible, highly scalable web crawler for production environment.
  • Crawler4j - Simple and lightweight web crawler.
  • JSoup - Scrapes, parses, manipulates and cleans HTML.

Web Frameworks

Frameworks that handle the communication between the layers of an web application.

  • Apache Tapestry - Component-oriented framework for creating dynamic, robust, highly scalable web applications.
  • Apache Wicket - Component-based web application framework similar to Tapestry with a stateful GUI.
  • Baratine - Toolkit for building distributed and reactive applications for multiple environments, either standalone or embedded.
  • Blade - Lightweight, modular framework which aims to be elegant and simple.
  • Bootique - Minimally opinionated framework for runnable apps.
  • Grails - Groovy framework with the aim to provide a highly productive environment by favoring convention over configuration, no XML and support for mixins.
  • Jooby - Scalable, fast and modular micro framework which offers multiple programming models.
  • Ninja - Full stack web framework.
  • Pippo - Small, highly modularized Sinatra-like framework.
  • Play - Uses convention over configuration, hot code reloading and display of errors in the browser.
  • PrimeFaces - JSF framework which has a free and a commercial version with support. Provides several frontend components.
  • Ratpack - Set of libraries that facilitate fast, efficient, evolvable and well tested HTTP applications.
  • Spring Boot - Microframework which simplifies the development of new Spring applications.
  • Vaadin - Event-driven framework build on top of GWT. Uses server-side architecture with Ajax on the client-side.

Resources

Communities

Active discussions.

  • r/java - Subreddit for the Java community.
  • stackoverflow - Question/answer platform.
  • vJUG - 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.

Influential Books

Books that had a high impact and are still worth reading.

Podcasts

Something to listen to while programming.

Twitter

Active accounts to follow. Descriptions from Twitter.

  • Adam Bien - Freelancer: Author, JavaONE Rockstar Speaker, Consultant, Java Champion.
  • Aleksey Shipilëv - Performance Geek, Benchmarking Tzar, Concurrency Bug Hunter.
  • Antonio Goncalves - Java Champion, JUG Leader, Devoxx France, Java EE 6/7, JCP, Author.
  • Arun Gupta - Java Champion, JavaOne Rockstar, JUG Leader, Devoxx4Kids-er, VP of Developer Advocacy at Couchbase.
  • Brian Goetz - Java Language Architect at Oracle.
  • Bruno Borges - Product Manager/Java Jock at Oracle.
  • Ed Burns - Consulting Member of the Technical Staff at Oracle.
  • Eugen Paraschiv - Author of the Spring Security Course.
  • James Weaver - Java/JavaFX/IoT developer, author and speaker.
  • Java EE - Official Java EE Twitter account.
  • Java Magazine - Official Java Magazine account.
  • Java - Official Java Twitter account.
  • Javin Paul - Well-known Java blogger.
  • Lukas Eder - Java Champion, speaker, JUG.ch co-leader, Founder and CEO Data Geekery (jOOQ).
  • Mario Fusco - RedHatter, JUG coordinator, frequent speaker and author.
  • Mark Reinhold - Chief Architect, Java Platform Group, Oracle.
  • Markus Eisele - Java EE evangelist, Red Hat.
  • Martijn Verburg - London JUG co-leader, speaker, author, Java Champion and much more.
  • Martin Thompson - Pasty faced performance gangster.
  • OpenJDK - Official OpenJDK account.
  • Peter Lawrey - Peter Lawrey, Java performance expert.
  • Reza Rahman - Java EE/GlassFish/WebLogic evangelist, author, speaker, open source hacker.
  • Simon Maple - Java Champion, virtualJUG founder, LJC leader, RebelLabs author.
  • Stephen Colebourne - Java Champion, speaker.
  • Trisha Gee - Java Champion and speaker.

Websites

Sites to read.

Contributing

Contributions are very welcome!

Please have a look at CONTRIBUTING for guidelines.