awesome-java

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

3 years after

Awesome Java Awesome

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

Ancients

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

  • Apache Ant - Build process management with XML.
  • cglib - Bytecode generation library.
  • GlassFish - Application server and reference implementation for Java EE sponsored by Oracle.
  • Hudson - Continuous integration server still in active development.
  • JavaServer Faces - Oracle's open-source implementation of the JSF standard, Mojarra.
  • JavaServer Pages - Common templating for websites with custom tag libraries.
  • Liquibase - Database-independent library for tracking, managing and applying database schema changes.

Build

Tools which handle the buildcycle 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.
  • Javassist - Tries to simplify the editing of bytecode.

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.
  • 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.
  • Error Prone - Catches common programming mistakes as compile-time errors.
  • FindBugs - Static analysis of bytecode to find 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.

Compiler-compiler

Frameworks that help to create parsers, interpreters or compilers.

  • ANTLR - Complex full-featured framework for top-down parsing.
  • JavaCC - More specific and slightly easier to learn. Has syntactic lookahead.

Configuration

Libraries that provide external configuration.

  • config - Configuration library for JVM languages.
  • owner - Reduces boilerplate of properties.

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.
  • Sat4J - State-of-the-art SAT solver for boolean and optimization problems.

Continuous Integration

Tools which support continuously building, testing and releasing applications.

  • Bamboo - Atlassian's solution with good integration of their other products. You can either apply for an open-source license or buy it.
  • CircleCI - Hosted service with a free trial.
  • Codeship - Hosted services with a limited free plan.
  • fabric8 - Integration platform for containers.
  • Go - ThoughtWork's open-source solution.
  • Jenkins - Provides server-based deployment services.
  • 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.

  • 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 Phoenix - High performance relational database layer over HBase for low latency applications.
  • Crate - Distributed data store that implements data synchronization, sharding, scaling, and replication. In addition, it provides a SQL-based syntax to execute queries across a cluster.
  • 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.
  • jOOQ - Generates typesafe code based on SQL schema.
  • MapDB - Embedded database engine that provides concurrent collections backed on disk or in off-heap memory.
  • Presto - Distributed SQL query engine for big data.
  • Querydsl - Typesafe unified queries.

Data structures

Efficient and specific data structures.

  • Apache Parquet - Columnar storage format based on assembly algorithms from the Dremel paper by Google.
  • 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.

  • Joda-Time - De facto standard date/time-library before Java 8.
  • 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.

  • ADT4J - JSR-269 code generator for algebraic data types.
  • AspectJ - Seamless aspect-oriented programming extension.
  • Auto - Collection of source code generators.
  • DCEVM - Modification of the JVM that allows unlimited redefinition of loaded classes at runtime.
  • HotswapAgent - Unlimited runtime class and resource redefinition.
  • Immutables - Scala-like case classes.
  • JHipster - Yeoman source code generator to create applications based on Spring Boot and AngularJS.
  • JRebel - Commercial software that instantly reloads code and configuration changes without redeploys.
  • Lombok - Code-generator which aims to reduce the verbosity.
  • Spring Loaded - Class reloading agent.
  • vert.x - Polyglot event-driven application framework.

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.
  • Hazelcast - Highly scalable in-memory datagrid.
  • 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.

Distribution

Tools which handle the distribution of applications in native formats.

  • Bintray - 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.
  • 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.
  • Launch4j - Wraps JARs in lightweight and native Windows executables.
  • Nexus - Binary management with proxy and caching capabilities.
  • packr - Packs JARs, assets and the JVM for native distribution on Windows, Linux and Mac OS X.

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.
  • jOpenDocument - Processes the OpenDocument format.

Functional Programming

Libraries that facilitate functional programming.

  • Cyclops - Monad and stream utilities, comprehensions, pattern matching, trampolines and much more.
  • 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.

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.

GUI

Libraries to create modern graphical user interfaces.

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.
  • fastutil - Fast and compact type-specific collections.
  • GS Collections - Collection framework inspired by Smalltalk.
  • HPPC - Primitive collections.
  • Javolution - Library for real-time and embedded systems.
  • JCTools - Concurrency tools currently missing from the JDK.
  • Koloboke - Hash sets and hash maps.
  • Trove - Primitive collections.

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 - 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.
  • Picasso - Image downloading and caching library for Android.
  • Thumbnailator - Thumbnailator is a high-quality thumbnail generation library for Java.
  • ZXing - Multi-format 1D/2D barcode image processing library.

JSON

Libraries that simplify JSON processing.

  • 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 - Similar to GSON but has performance gains if you need to instantiate the library more often.
  • LoganSquare - JSON parsing and serializing library based on Jackson's streaming API. Outpeforms GSON & Jackson's library.

JVM and JDK

Current implementations of the JVM/JDK.

  • JDK 9 - Early access releases of JDK 9.
  • OpenJDK - Open-source implementation.

Languages

Languages other than Java that can be used to write JVM applications.

  • Scala - Statically typed programming language that fuses the object - oriented model and functional programming ideas.
  • Groovy - Optionally typed and dynamic language, with static-typing and static compilation capabilities. Currently an incubating Apache project
  • Clojure - Dynamically typed programming language that can be seen as a modern take on Lisp.
  • Ceylon - Statically typed object-oriented language developed by RedHat.
  • Kotlin - JetBrain's statically typed programming language for the JVM, Android and the browser.

Logging

Libraries that log the behavior of an application.

  • Apache Log4j 2 - Complete rewrite with a powerful plugin and configuration architecture.
  • kibana - Analyzes and visualizes log files.
  • Logback - Robust logging library with interesting configuration options via Groovy.
  • logstash - Tool for managing log files.
  • Metrics - Expose metrics via JMX or HTTP and can send them to a database.
  • SLF4J - Abstraction layer which is to be used with an implementation.

Machine Learning

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

  • Apache Flink - Fast and reliable large-scale data processing engine.
  • Apache Hadoop - Storage and large-scale processing of data-sets on clusters of commodity hardware.
  • Apache Mahout - Scalable algorithms focused on collaborative filtering, clustering and classification.
  • Apache Spark - Data analytics cluster computing framework.
  • 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.
  • 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.
  • JBoss HornetQ - Clear, concise, modular and made to be embedded.
  • JeroMQ - Implementation of ZeroMQ.
  • Smack - Cross-platform XMPP client library.

Miscellaneous

Everything else.

  • Design Patterns - Implementation and explanation of the most common design patterns.
  • Jimfs - In-memory file system.
  • Lanterna - Easy console text GUI library similar to curses.
  • LightAdmin - Pluggable CRUD UI library for rapid application development.
  • OpenRefine - Tool for working with messy data: cleaning, transforming, extending it with web services and linking it to databases.
  • RoboVM - Commercial framework with a free trial to write native iOS apps.

Monitoring

Tools that monitor applications in production.

  • AppDynamics - Commercial performance monitor.
  • JavaMelody - Performance monitoring and profiling.
  • Kamon - Tool for monitoring applications running on the JVM.
  • New Relic - Commercial performance monitor.
  • SPM - Commercial performance monitor with distributing transaction tracing for JVM apps.
  • Takipi - Commercial in-production error monitoring and debugging.

Native

For working with platform-specific native libraries.

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

Natural Language Processing

Libraries that specialize on processing text.

  • Apache OpenNLP - Toolkit for common tasks like tokenization.
  • CoreNLP - Stanford's CoreNLP provides a set of fundamental tools for tasks like tagging, named entity recognition, sentiment analysis and many more.
  • LingPipe - Toolkit for a variety of tasks ranging from POS tagging to sentiment analysis.
  • Mallet - Statistical natural language processing, document classification, clustering, topic modeling and more.

Networking

Libraries for network programming.

  • Async Http Client - Asynchronous HTTP and WebSocket client library.
  • Grizzly - NIO framework. Used as a network layer in Glassfish.
  • Netty - Framework for building high performance network applications.
  • OkHttp - HTTP+SPDY client.
  • Undertow - Web server providing both blocking and non-blocking API’s based on NIO. Used as a network layer in WildFly.

ORM

APIs which handle the persistence of objects.

  • 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.
  • OrmLite - Lightweight package avoiding the complexity and overhead of other ORM products.

PDF

Everything that helps with the creation of PDF files.

Performance analysis

Tools for performance analysis, profiling and benchmarking.

  • jHiccup - Logs and records platform JVM stalls.
  • JMH - Microbenchmarking tool for the JVM.
  • JProfiler - Commercial profiler.
  • LatencyUtils - Utilities for latency measurement and reporting.
  • VisualVM - Visual interface for detailed information about running applications.
  • YourKit Java Profiler - Commercial profiler.

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.

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.
  • 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.
  • RestX - Framework based on annotation processing and compile-time source generation.
  • 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 and analysis.

  • DataMelt - Environment for scientific computation, data analysis and data visualization.
  • JGraphT - Graph library that provides mathematical graph-theory objects and algorithms.
  • JScience - Provides a set of classes to work with scientific measurements and units.

Search

Engines which index documents for search and analysis.

  • 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.
  • Keycloak - Integrated SSO and IDM for browser apps and RESTful web services.
  • 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.
  • Kryo - Fast and efficient object graph serialization framework.
  • FST - JDK compatible high performance object graph serialization.
  • 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.
  • 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.

  • Apache Velocity - Templates for HTML pages, emails or source code generation in general.
  • FreeMarker - General templating engine without any heavyweight or opinionated dependencies.
  • Handlebars.java - Logic-less and semantic Mustache templates.
  • 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.
  • Cucumber - BDD testing framework.
  • Gatling - Load testing tool designed for ease of use, maintainability and high performance.
  • Hamcrest - Matchers that can be combined to create flexible expressions of intent.
  • JMockit - Mocks static, final methods and more.
  • JUnit - Common testing framework.
  • Mockito - Creation of test double objects in automated unit tests for the purpose of TDD or BDD.
  • PowerMock - Enables mocking of static methods, constructors, final classes and methods, private methods and removal of static initializers.
  • 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.
  • TestNG - Testing framework.
  • Truth - Google's assertion and proposition framework.
  • Unitils - Modular testing library for unit and integration testing.
  • WireMock - Stubbs 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.
  • args4j - Command line arguments parser.
  • CRaSH - Provides a CLI for running processes.
  • 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.
  • javatuples - Tuples.
  • JCommander - Command line arguments parser.
  • Protégé - Provides an ontology editor and a framework to build knowledge-based systems.

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.
  • Google Web Toolkit - 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.
  • Grails - Groovy framework with the aim to provide a highly productive environment by favoring convention over configuration, no XML and support for mixins.
  • 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.
  • Spring - Provides many packages ranging from dependency injection to aspect-oriented programming to security.
  • 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.

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, UG Leader, Devoxx4Kids-er, Red Hatter.
  • 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.net - Official Java.net account.
  • Java - Official Java Twitter account.
  • Javin Paul - Well-known Java blogger.
  • Lukas Eder - 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.
  • Roberto Cortez - Java EE/JPA expert, speaker, open source.
  • Simon Maple - Java Champion, virtualJUG founder, LJC leader, RebelLabs author.
  • Stephen Colebourne - Java Champion, speaker.
  • Tim Boudreau - Author and NetBeans guru.
  • Trisha Gee - Java Champion and speaker.

Websites

Sites to read.

Contributing

Contributions are very welcome!

Please have a look at CONTRIBUTING for guidelines.