A curated list of awesome Java frameworks, libraries and software. Inspired by awesome-python.

• Awesome Java
  • Build Tool
  • Code Analysis
  • Compiler-compiler
  • Continuous Integration
  • Database
  • Date and Time
  • Dependency Injection
  • Development
  • Distributed Applications
  • Distribution
  • Document Processing
  • GUI
  • Game Development
  • High Performance
  • HTTP
  • IDE
  • JVM and JDK
  • JSON
  • Logging
  • Machine Learning
  • Messaging
  • Miscellaneous
  • Natural Language Processing
  • Networking
  • ORM
  • PDF
  • Security
  • Science
  • Server
  • Template Engine
  • Testing
  • Utility
  • Visualization
  • Web Crawling
  • Web Frameworks
  • REST Frameworks
• Resources
  • Communities
  • Influential Books
  • Podcasts
  • Twitter
  • Websites
• Contributing

Tools which handle the buildcycle of an application.

• Apache Maven - Declarative build and dependency management which favors convention over configuration. It's preferable to Apache Ant which uses a rather procedural approach and can be rather difficult to maintain.
• Gradle - Incremental builds which are programmed via Groovy instead of declaring XML. Works well with Maven's dependency management and treats Ant scripts as first-class citizens.

Tools that provide metrics and quality measurements of static code.

• SonarQube - Inspection tool for code quality. It integrates with several external tools like Gradle, Jira and Jenkins and provides an overview of the metrics over time.
• FindBugs - Static analysis of bytecode to find potential bugs.
• Metrics - Measures the behavior of critical components.

Tools that 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.

Tools which support continuously building, testing and releasing applications.

• Jenkins - Provides server-based services. Often seen as the successor to Hudson, although it is still actively developed.
• Travis - A hosted continuous integration service that integrates with GitHub repositories.
• Shippable - Based on Docker, it provides also Bitbucket integration.

Everything which simplifies interactions with the database.

• jOOQ - Generates typesafe code based on SQL schema.
• Liquibase - Source control for your database which can be embedded.

Libraries related to date and time.

• Java 8 SE: Date and Time API - Basically, it incorporates Joda-Time.
• Joda-Time - De facto standard date/time-library before Java 8.

Libraries that help to realize the Inversion of Control paradigm.

• Dagger - Compile-time injection framework without reflection, mainly for Android.
• Google Guice - Lightweight but powerful framework.
• Spring - Only Spring Context is needed for injections.
• Weld - CDI reference implementation.

Integrated environments that augment the process of development at a fundamental level, e.g. classloading.

• DCEVM - Modification of the JVM that allows unlimited redefinition of loaded classes at runtime.
• JRebel - Instantly reloads code and configuration changes without redeploys.

Libraries and frameworks used to ease writing distributed and fault-tolerant applications.

• Akka - Toolkit and runtime for building highly concurrent, distributed, and fault tolerant event-driven applications.
• JGroups - Toolkit for reliable messaging and creating clusters whose nodes can send messages to each other.
• Apache ZooKeeper - Coordination service with distributed configuration, synchronization, and naming registry for large distributed systems.

Tools which handle the distribution of Java applications in native formats.

• Launch4j - Wraps JARs in lightweight and native Windows executables.
• packr - Packs your JAR, assets and JVM for native distribution on Windows, Linux and Mac OS X.
• Bintray - Version control for your binaries which handles the publishing. Can also be used with Maven or Gradle.

Libraries that assist with processing office document formats.

• Apache POI - Supports OOXML (e.g XLSX, DOCX, PPTX) as well as OLE2 (e.g. XLS, DOC or PPT).
• jOpenDocument - Processes the OpenDocument format.

Libraries to create modern graphical user interfaces.

• JavaFX - The successor of Swing.
• Scene Builder - Visual layout tool for JavaFX applications.

Frameworks that support the development of games.

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

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

• Trove - Primitive collections.
• HPPC - Primitive collections.
• Disruptor - Inter-thread messaging library.
• Javalution - Library for real-time and embedded systems.

Libraries for working with HTTP.

• OkHttp - An HTTP+SPDY client for Android and Java applications.

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

• NetBeans - Provides integration for several Java SE and EE features starting with database access and servers to HTML5 and AngularJS.
• Eclipse - Does a lot of things in the background. Noteworthy are its large amount of plugins.
• IntelliJ IDEA - Supports a lot of JVM languages and provides good options for Android development. The commercial edition targets the enterprise sector.

Various implementations of the JVM/JDK.

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

Libraries that simplify JSON processing.

• Google Gson - Serializes Java 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.

Libraries that log the behavior of an application.

• Apache Log4j 2 - Complete rewrite of the previous version. Now has a powerful plugin and configuration architecture.
• Logback - Founded by the same developer as Log4j and proves to be a robust logging library with interesting configuration options via Groovy.
• SLF4J - Abstraction layer which is to be used with an implementation.

Tools that provide specific statistical algorithms which allow to learn from data.

• Apache Hadoop - Open-source software framework for 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 - Open-source data analytics cluster computing framework.
• Weka - Collection of algorithms for data mining tasks ranging from pre-processing to visualization.

Tools that help sending messages between clients to ensure protocol independency.

• Apache ActiveMQ - Open-source message broker that implements JMS and converts synchronous to asynchronous communication.
• Apache Kafka - High-throughput distributed messaging system.
• JBoss HornetQ - Clear, concise, modular and made to be embedded.

Everything else.

• Jimfs - In-memory file system.
• Lanterna - Easy console text GUI library similar to curses.
• Lombok - Code-generator which aims to reduce the verbosity of Java.
• RoboVM - Write native iOS apps in Java.

Libraries that specialize on processing text.

• Apache OpenNLP - Toolkit for common tasks like tokenization.
• LingPipe - Toolkit for a variety of tasks ranging from POS tagging to sentiment analysis.
• Mallet - Statistical natural language processing, document classification, clustering, topic modeling, etc.

Libraries for network programming.

• Netty - A framework for building high performance network applications.

APIs which handle the persistence of objects.

• EclipseLink - Supports a number of persistence standards: JPA, JAXB, JCA and SDO.
• Hibernate - Robust and widely used with an active community.

Everything that helps with the creation of PDF files.

• Apache FOP - Creates PDF from XSL-FO.
• Apache PDFBox - Toolbox for creating and manipulating PDF.
• JasperReports - Complex reporting engine.
• DynamicReports - Simplifies JasperReports.
• iText - Easy to use PDF library which creates PDF files programmatically but requires a license for commercial purposes.

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

• Apache Shiro - Performs authentication, authorization, cryptography and session management.
• Keycloak - Integrated SSO and IDM for browser apps and RESTful web services. Currently in beta but looks very promising.
• PicketLink - PicketLink is an umbrella project for security and identity management for Java applications.
• Spring Security - Focuses on authentication/authorization and protects against several attack vectors.

Libraries for scientific computing and analysis.

• JScience - Comprehensive framework of science related libraries.
• JTransforms - Multithread FFT library.
• Parallel Colt - Multithread high performance scientific and technical computing.
• SCaVis - Environment for scientific computation, data analysis and data visualization.

Servers which are specifically used to deploy applications.

• GlassFish - Open source reference implementation for Java EE sponsored by Oracle.
• WildFly - Formerly known as JBoss and developed by Red Hat with extensive Java EE support.
• Jetty - Lightweight, small server, often embedded in projects.
• Apache Tomcat - Robust all-round server for Servlet and JSP.
• Apache TomEE - Tomcat plus Java EE.

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.
• JavaServer Pages - Aged templating for websites with custom tag libraries.
• Thymeleaf - Aims to be a substitute for JSP and works for XML files in general.

Tools that test from object to interface level including performance and other benchmarks.

• AssertJ - Fluent assertions.
• Apache JMeter - Functional testing and performance measurements.
• Arquillian - Integration and functional testing platform with integration of Java EE containers.
• Calipher - Microbenchmarking framework.
• FEST - Collection of testing libraries.
• Hamcrest - Framework for writing declarative assertion matchers.
• JMH - Microbenchmarking.
• JUnit - Testing framework.
• Mockito - Creation of test double objects in automated unit tests for the purpose of TDD or BDD.
• Selenium - Portable software testing framework for web applications.
• TestNG - Testing framework.
• VisualVM - Visual interface for viewing detailed information about Java applications while they are running on a JVM.

Libraries which provide unspecific functionality, e.g. optimized datastructures.

• Apache Commons - Provides different general purpose functions like configuration, validation, collections, file upload or XML processing.
• Google Guava - Collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and so forth.
• javatuples - Does what it says, although the concept of tuples in general is debatable.

Libraries or frameworks which allow you to visualize data.

• Processing - A project deeply rooted in visual art which allows you to program the visualization of data.

Libraries that analyze the content of websites.

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

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 in Java.
• Spring - Aims to simplify the development with Java EE and provides packages for dependency injection and aspect-oriented programming.
• 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.
• 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.
• Apache Wicket - Component-based web application framework similar to Tapestry with a stateful GUI.
• 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.
• Spark - Unique framework which focuses not on complex MVC patterns but on rapid development.

Frameworks specifically for creating RESTful services.

• Dropwizard - Opinionated framework for setting up modern web applications, includes Jetty, Jackson, Jersey and Metrics.
• Jersey - JAX-RS reference implementation.
• RESTEasy - Fully certified and portable implementation of the JAX-RS specification.
• Retrofit - A type-safe REST client for Java.

Active discussions.

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

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

• Effective Java (2nd Edition)
• Java Concurrency in Practice
• Thinking in Java

Something to listen to while programming.

• The Java Posse

People to follow.

• Adam Bien
• Antonio Goncalves
• Arun Gupta
• Ed Burns
• Java
• Java EE
• Java.net
• Java Magazine
• Mark Reinhold
• OpenJDK
• Pete Muir
• Reza Rahman
• Simon Maple
• Tim Boudreau

Sites to read.

• Java.net
• JavaWorld
• Javalobby

Contributions are very welcome!

Please have a look at CONTRIBUTING for guidelines.

Topics which have no libraries as of yet are located in TOPICS.