akullpp/awesome-java

Projects

Database

QueryStreamstars9 - Build JPA Criteria queries using a Stream-like API.

QuestDBstars8.8k - High-performance SQL database for time series. Supports InfluxDB line protocol, PostgreSQL wire protocol, and REST.

Spring Data JPA MongoDB Expressionsstars84 - Allows you to use MongoDB query language to query your relational database.

Trino - Distributed SQL query engine for big data.

Projects

Distribution

jDeploy - Deploy desktop apps as native Mac, Windows or Linux bundles.

Resources

Podcasts and Screencasts

140 Second Ducklings - Short videos on Twitter explaining Java debugging in depth.

Projects

Configuration

Externalized Propertiesstars14 - Lightweight but powerful configuration library which supports resolution of properties from external sources and an extensible post-processing/conversion mechanism.

Projects

Date and Time

Jollydaystars170 - Determines the holidays for a given year, country/name and eventually state/region.

Projects

Logging

Echopraxiastars37 - API designed around structured logging, rich context, and conditional logging. There are Logback and Log4J2 implementations, but Echopraxia's API is completely dependency-free, meaning it can be implemented with any logging API.

Projects

Miscellaneous

RR4Jstars13 - RR4J is a tool that records java bytecode execution and later allows developers to replay locally.

Projects

Code Generators

JPA Buddy - Plugin for IntelliJ IDEA. Provides visual tools for generating JPA entities, Spring Data JPA repositories, Liquibase changelogs and SQL scripts. Offers automatic Liquibase/Flyway script generation by comparing model to DB, and reverse engineering JPA entities from DB tables.

Gecistars107 - Discovers files that need generated code, updates automatically and writes to the source with a convenient API.

Projects

Security

jwt-javastars7 - Easily create and parse JSON Web Tokens and create customized JWT validators using a fluent API.

Resources

Other

Groundbreakers - Oracle ACEs, Groundbreaker Ambassadors and Java Champions.

Projects

Template Engine

Jamalstars18 - Extendable template engine embedded into Maven/JavaDoc, supporting multiple extensions (Groovy, Ruby, JavaScript, JShell, PlantUml) with support for snippet handling.

jtestars394 - Compiles to classes, and uses an easy syntax, several features to make development easier and provides fast execution and a small footprint.

Projects

Monitoring

Sentry stars835 - Integration with Sentrystars31.2k, an application error tracking and performance analysis platform.

Projects

Miscellaneous

JObfuscator - Source code obfuscator.

Projects

Database

ArangoDBstars187 - ArangoDB Java driver.

Resources

Twitter

Lukas Eder - Java Champion, speaker, Founder and CEO Data Geekery (jOOQ).

Projects

Code Generators

Record-Builderstars312 - Companion builder class, withers and templates for Java records.

Projects

Miscellaneous

ConsoleCaptorstars12 - Captures console output for unit testing purposes.

Projects

Workflow Orchestration Engines

flowablestars5.3k - Compact and efficient workflow and business process management platform.

Projects

Machine Learning

m2cgenstars2.1k - CLI tool to transpile models into native code.

Projects

Financial

Cassandrestars377 - Trading bot framework.

Projects

CLI

jbockstars69 - Reflectionless command line parser.

Projects

Utility

Java Diff Utils - Utilities for text or data comparison and patching.

Projects

IDE

Recaf - Bytecode editor.

Projects

Networking

Commons-networkingstars4 - Client for server-sent events (SSE).

Projects

Code Generators

Bootify - Browser-based Spring Boot app generation with JPA model and REST API.

Projects

Template Engine

StringTemplatestars809 - Template engine for generating source code, web pages, emails, or any other formatted text output.

Projects

Workflow Orchestration Engines

Cadence - Stateful code platform from Uber.

Temporal - Microservice orchestration platform, forked from Cadence but gRPC based.

Projects

ORM

ObjectiveSqlstars1.2k - ActiveRecord ORM for rapid development and convention over configuration.

Projects

Miscellaneous

Smooksstars344 - Framework for fragment-based message processing. (Apache-2.0 OR LGPL-3.0-or-later)

Projects

CSV

FastCSVstars377 - Performance-optimized, dependency-free and RFC 4180 compliant.

Projects

Financial

ta4jstars1.5k - Library for technical analysis.

Projects

Security

OTP-Javastars73 - One-time password generator library according to RFC 4226 (HOTP) and RFC 6238 (TOTP).

Projects

Distribution

Artipiestars259 - Binary artifact management toolkit which hosts them on the file system or S3.

Projects

Security

Password4jstars198 - User-friendly cryptographic library that supports Argon2, Bcrypt, Scrypt, PBKDF2 and various other cryptographic hash functions.

Projects

Game Development

JBox2D - Port of the renowned C++ 2D physics engine.

libGDX - All-round cross-platform, high-level framework.

Litiengine - AWT-based, lightweight 2D game engine.

Projects

Computer Vision

BoofCV - Library for image processing, camera calibration, tracking, SFM, MVS, 3D vision, QR Code and much more.

Projects

Miscellaneous

jsweetstars1.3k - Source transpiler to TypeScript/JavaScript.

Projects

Computer Vision

ImageJ - Medical image processing application with an API.

JavaCVstars6k - Java interface to OpenCV, FFmpeg, and much more.

Projects

HTTP Clients

Google HTTP Clientstars1.2k - Pluggable HTTP transport abstraction with support for java.net.HttpURLConnection, Apache HTTP Client, Android, Google App Engine, XML, Gson, Jackson and Protobuf.

Projects

Distribution

Getdownstars455 - A system for deploying Java applications to end-user computers and keeping them up to date. Developed as an alternative to Java Web Start.

JavaPackagerstars547 - Maven and Gradle plugin which provides an easy way to package Java applications in native Windows, Mac OS X or GNU/Linux executables, and generate installers for them.

Projects

Data Structures

RoaringBitmapstars2.7k - Fast and efficient compressed bitmap.

Projects

Document Processing

fastexcelstars393 - High performance library to read and write large Excel (XLSX) worksheets.

Resources

Websites

foojay.io

Resources

Podcasts and Screencasts

A Bootiful Podcast

Inside Java (Official)

Projects

Configuration

Configuratestars240 - Configuration library with support for various configuration formats and transformations.

Projects

Networking

sshjstars2.1k - Programmatically use SSH, SCP or SFTP.

Projects

Science

BioJava - Facilitates processing biological data by providing algorithms, file format parsers, sequencing and 3D visualization commonly used in bioinformatics.

Resources

Related Awesome Lists

Awesome Graalstars332

Resources

Twitter

Mani Sarkar - Java champion, Polyglot, Software Crafter involved with @graalvm, AI/ML/DL, Data Science, Developer communities, speaker & blogger. Creator of couple of awesome lists like this one.

Projects

Miscellaneous

LogCaptorstars191 - Captures log entries for unit testing purposes.

Projects

Machine Learning

oj! Algorithms - High-performance mathematics, linear algebra and optimisation needed for data science, machine learning and scientific computing.

Tribuo - Provides tools for classification, regression, clustering, model development and interfaces with other libraries such as scikit-learn, pytorch and TensorFlow.

DJL - High-level and engine-agnostic framework for deep learning.

Projects

Microservice

ActiveRPC - Lightweight and fast library for complex high-load distributed applications and Memcached-like solutions.

Projects

PDF

Tabulastars1.4k - Extracts tables from PDF files.

Projects

Native

Aparapistars409 - Converts bytecode to OpenCL which allows execution on GPUs.

Projects

Science

Chart-FXstars348 - Scientific charting library with focus on performance optimised real-time data visualisation at 25 Hz update rates for large data sets.

LogicNGstars90 - Library for creating, manipulating and solving Boolean and Pseudo-Boolean formulas.

Projects

Security

SSLContext-Kickstartstars244 - High-level SSL context builder for configuring HTTP clients with SSL/TLS.

Projects

HTTP Clients

Apache HttpComponents - A toolset of low level Java components focused on HTTP and associated protocols.

methanolstars146 - HTTP client extensions library.

Projects

Machine Learning

H2O - Analytics engine for statistics over big data.

Siddhistars1.3k - Cloud native streaming and complex event processing engine.

Projects

Monitoring

Datadog stars338 - Modern monitoring & analytics.

Prometheusstars1.8k - Provides a multi-dimensional data model, DSL, autonomous server nodes and much more.

SPM stars19 - Performance monitor with distributing transaction tracing for JVM apps.

Projects

Template Engine

Jtwigstars298 - Modular, configurable and fully tested template engine.

Projects

Database

Xodusstars997 - Highly concurrent transactional schema-less and ACID-compliant embedded database.

Apache Calcite - Dynamic data management framework. It contains many of the pieces that comprise a typical database management system.

Projects

Distributed Transactions

Seatastars22.4k - Delivers high performance and easy to use distributed transaction services under a microservices architecture.

Projects

High Performance

Kolobokestars962 - Carefully designed extension of the Java Collections Framework with primitive specializations and more.

Projects

Hypermedia Types

Siren4Jstars23 - Library for the Siren specification.

Projects

Web Frameworks

ActiveJ - Lightweight asynchronous framework built from the ground up for developing high-performance web applications.

Projects

Mobile Development

Codename One - Cross-platform solution for writing native mobile apps. (GPL-2.0-only WITH Classpath-exception-2.0)

MobileUI - Cross-platform framework for developing mobile apps with native UI in Java and Kotlin.

Multi-OS Engine - Open-source, cross-platform engine to develop native mobile (iOS, Android, etc.) apps.

Projects

Code Generators

Telosys - Simple and light code generator available as an Eclipse Plugin and also as a CLI.

Projects

Configuration

microconfig - Configuration system designed for microservices which helps to separate configuration from code. The configuration for different services can have common and specific parts and can be dynamically distributed.

Projects

Job Scheduling

easy-batchstars553 - Set up batch jobs with simple processing pipelines. Records are read in sequence from a data source, processed in pipeline and written in batches to a data sink.

shedlockstars2.5k - Makes sure that your scheduled tasks are executed at most once at the same time. If a task is being executed on one node, it acquires a lock which prevents execution of the same task from another node or thread.

Projects

Game Development

Mini2Dx - Beginner-friendly, master-ready framework for rapidly prototyping and building 2D games.

Projects

Database

Debezium - Low latency data streaming platform for change data capture.

Projects

Job Scheduling

JobRunrstars1k - Job scheduling library which utilizes lambdas for fire-and-forget, delayed and recurring jobs. Guarantees execution by single scheduler instance using optimistic locking. Has features for persistence, minimal dependencies and is embeddable.

Projects

Configuration

configstars5.7k - Configuration library supporting Java properties, JSON or its human optimized superset HOCON.

Projects

Imagery

image-comparisonstars214 - 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.

Projects

PDF

Eclipse BIRT - Report engine for creating PDF and other formats (DOCX, XLSX, HTML, etc) using Eclipse-based visual editor.

Projects

Template Engine

Freemarker - Library to generate text output (HTML web pages, e-mails, configuration files, source code, etc.) based on templates and changing data.

Projects

Hypermedia Types

hatestars20 - Builds hypermedia-friendly objects according to HAL specification.

Projects

JVM and JDK

Dragonwell8stars3.6k - Downstream version of OpenJDK optimized for online e-commerce, financial, logistics applications.

Projects

Microservice

Sentinelstars19.3k - Flow control component enabling reliability, resilience and monitoring for microservices.

Projects

Utility

Arthasstars29.5k - Allows to troubleshoot production issues for applications without modifying code or restarting servers.

Projects

Development

Tail - Enable infinite recursion using tail call optimization.

Projects

Distribution

Cloudsmith - Fully managed package management SaaS with support for Maven/Gradle/SBT with a free tier.

Projects

ORM

Permazenstars301 - Language-natural persistence layer.

Projects

Asynchronous

Karatestars6.1k - DSL that combines API test-automation, mocks and performance-testing making testing REST/HTTP services easy.

Projects

Logging

Logstash - Tool for managing log files.

Projects

Distributed Applications

Hazelcaststars4.9k - Highly scalable in-memory datagrid with a free open-source version.

Axon - Framework for creating CQRS applications.

Quasar - Lightweight threads and actors for the JVM.

ScaleCube Services - Embeddable Cluster-Membership library based on SWIM and gossip protocol.

Zuulstars12k - Gateway service that provides dynamic routing, monitoring, resiliency, security, and more.

Projects

Functional Programming

Cyclopsstars1.2k - Monad and stream utilities, comprehensions, pattern matching, functional extensions for all JDK collections, future streams, trampolines and much more.

Vavr - Functional component library that provides persistent data types and functional control structures.

Projects

Game Development

FXGL - JavaFX Game Development Framework.

jMonkeyEngine - Game engine for modern 3D development.

Projects

Geospatial

Jgeohash - Library for using the GeoHash algorithm.

H2GIS - Spatial extension of the H2 database. (LGPL-3.0-only)

Projects

GUI

Scene Builder - Visual layout tool for JavaFX applications.

SWT - Graphical widget toolkit.

JavaFX - Successor of Swing.

Projects

High Performance

Disruptor - Inter-thread messaging library.

Projects

HTTP Clients

Feignstars8.1k - HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.

restQL-java - Microservice query language that fetches information from multiple services.

Retrofit - Typesafe REST client.

Projects

IDE

IntelliJ IDEA - Supports many JVM languages and provides good options for Android development. The commercial edition targets the enterprise sector.

Projects

Imagery

Imgscalrstars1.1k - Simple, efficient and hardware-accelerated image-scaling library implemented in pure Java 2D.

Tess4Jstars1.2k - JNA wrapper for Tesseract OCR API.

Projects

Introspection

Mirror - Mirror was created to bring light to a simple problem, usually named ReflectionUtil, which is on almost all projects that rely on reflection to do advanced tasks.

Projects

JSON

Genson - Powerful and easy-to-use Java-to-JSON conversion library.

Yassonstars180 - Binding layer between classes and JSON documents similar to JAXB.

JsonPathstars7.1k - Extract data from JSON using XPATH-like syntax.

Projects

JVM and JDK

Corretto - No-cost, multiplatform, production-ready distribution of OpenJDK by Amazon. (GPL-2.0-only WITH Classpath-exception-2.0)

Liberica JDK - Built from OpenJDK, thoroughly tested and passed the JCK. (GPL-2.0-only WITH Classpath-exception-2.0)

SAP Machine - SAP's no-cost, rigorously tested and JCK-verified OpenJDK friendly fork. (GPL-2.0-only WITH Classpath-exception-2.0)

Zulu - OpenJDK builds for Windows, Linux, and macOS. (GPL-2.0-only WITH Classpath-exception-2.0)

Projects

Logging

Apache Log4j 2 - Complete rewrite with a powerful plugin and configuration architecture.

Kibana - Analyzes and visualizes log files. Some features require payment.

Logback - Robust logging library with interesting configuration options via Groovy.

tinylog - Lightweight logging framework with static logger class.

OpenTracing Toolboxstars181 - Collection of libraries that build on top of OpenTracing and provide extensions and plugins to existing instrumentations.

SLF4J - Abstraction layer/simple logging facade.

Projects

Machine Learning

Weka - Collection of algorithms for data mining tasks ranging from pre-processing to visualization. (GPL-3.0-only)

Smilestars5.5k - Statistical Machine Intelligence and Learning Engine provides a set of machine learning algorithms and a visualization library.

Projects

Messaging

NATS clientstars419 - NATS client.

Projects

Microservice

Apollo - Libraries for writing composable microservices.

Micronaut - Modern full-stack framework with focus on modularity, minimal memory footprint and startup time.

Armeriastars3.7k - Asynchronous RPC/REST client/server library built on top of Java 8, Netty, HTTP/2, Thrift and gRPC.

consul-apistars396 - Client for the Consul API: a distributed, highly available and datacenter-aware registry/discovery service.

Eurekastars11.3k - REST-based service registry for resilient load balancing and failover.

Helidon - Two-style approach for writing microservices: Functional-reactive and as an implementation of MicroProfile.

Nacos - Dynamic service discovery, configuration and service management platform for building cloud native applications.

Quarkus - Kubernetes stack tailored for the HotSpot and Graal VM.

Projects

Miscellaneous

JBake - Static website generator.

JBotstars1.2k - Framework for building chatbots. (GPL-3.0-only)

Joda-Money - Basic currency and money classes and algorithms not provided by the JDK.

Modernizer - Detect uses of legacy Java APIs.

OctoLinkerstars5k - Browser extension which allows to navigate through code on GitHub more efficiently.

Membrane Service Proxystars377 - Open-source, reverse-proxy framework.

PipelinRstars240 - Small utility library for using handlers and commands with pipelines.

Simple Java Mailstars979 - Mailing with a clean and fluent API.

Projects

Monitoring

Failsafe Actuatorstars52 - Out of the box monitoring of Failsafe Circuit Breaker in Spring-Boot environment.

inspectIT - 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.

Metricsstars7.6k - Expose metrics via JMX or HTTP and send them to a database.

Projects

Natural Language Processing

LingPipe - Toolkit for tasks ranging from POS tagging to sentiment analysis.

Projects

Networking

Dubbostars37.5k - High-performance RPC framework.

Grizzly - NIO framework. Used as a network layer in Glassfish.

Driftstars213 - Easy-to-use, annotation-based library for creating Thrift clients and serializable types.

Projects

ORM

Domastars323 - 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.

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. (LGPL-2.1-only)

MyBatisstars17.3k - Couples objects with stored procedures or SQL statements.

Projects

PaaS

AWS Elastic Beanstalk - AWS-based, with support for Tomcat and Jetty.

AWS Lambda - Serverless computation.

Microsoft Azure - Microsoft's cloud infrastructure.

Projects

PDF

Apache FOP - Creates PDFs from XSL-FO.

iText - Creates PDF files programmatically.

Projects

Performance analysis

fastThread - Analyze and visualize thread dumps with a free cloud-based upload interface.

GCeasy - Tool to analyze and visualize GC logs. It provides a free cloud-based upload interface.

JMH - Harness for building, running, and analysing nano/micro/milli/macro benchmarks written in Java and other languages targeting the JVM. (GPL-2.0 only WITH Classpath-exception-2.0)

honest-profilerstars1.2k - Low-overhead, bias-free sampling profiler.

Projects

Apache Commons

BCEL - Byte Code Engineering Library - analyze, create, and manipulate Java class files.

BeanUtils - Easy-to-use wrappers around the Java reflection and introspection APIs.

BeanUtils2 - Redesign of Commons BeanUtils.

BSF - Bean Scripting Framework - interface to scripting languages, including JSR-223.

Chain - Chain of Responsibility pattern implementation.

ClassScan - Find Class interfaces, methods, fields, and annotations without loading.

CLI - Command-line arguments parser.

CLI2 - Redesign of Commons CLI.

Codec - General encoding/decoding algorithms, e.g. phonetic, base64 or URL.

Collections - Extends or augments the Java Collections Framework.

Compress - Defines an API for working with tar, zip and bzip2 files.

Configuration - Reading of configuration/preferences files in various formats.

Convert - Commons-Convert aims to provide a single library dedicated to the task of converting an object of one type to another.

CSV - Component for reading and writing comma separated value files.

Daemon - Alternative invocation mechanism for unix-daemon-like java code.

DBCP - Database connection pooling services.

DbUtils - JDBC helper library.

Digester - XML-to-Java-object mapping utility.

Email - Library for sending e-mail from Java.

Exec - API for dealing with external process execution and environment management in Java.

FileUpload - File upload capability for your servlets and web applications.

Finder - Java library inspired by the UNIX find command.

Flatfile - Java library for working with flat data structures.

Functor - Function that can be manipulated as an object, or an object representing a single, generic function.

Graph - General purpose graph APIs and algorithms.

I18n - Adds the feature of localized message bundles that consist of one or many localized texts that belong together.

Id - Id is a component used to generate identifiers.

Imaging - Image library.

IO - Collection of I/O utilities.

Javaflow - Continuation implementation to capture the state of the application.

JCI - Java Compiler Interface.

JCS - Java Caching System.

Jelly - XML based scripting and processing engine.

Jexl - Expression language which extends the Expression Language of the JSTL.

JNet - JNet allows to use dynamically register url stream handlers through the java.net API.

JXPath - Utilities for manipulating Java Beans using the XPath syntax.

Lang - Provides extra functionality for classes in java.lang.

Logging - Wrapper around a variety of logging API implementations.

Math - Lightweight, self-contained mathematics and statistics components.

Monitoring - Monitoring aims to provide a simple but extensible monitoring solution for Java applications.

Nabla - Nabla provides automatic differentiation classes that can generate derivative of any function implemented in the Java language.

Net - Collection of network utilities and protocol implementations.

OGNL - Object-graph navigation language.

OpenPGP - Interface to signing and verifying data using OpenPGP.

Performance - Small framework for microbenchmark clients, with implementations for Commons DBCP and Pool.

Pipeline - Provides a set of pipeline utilities designed around work queues that run in parallel to sequentially process data objects.

Pool - Generic object pooling component.

Proxy - Library for creating dynamic proxies.

RDF - Common implementation of RDF 1.1 that could be implemented by systems on the JVM.

RNG - Commons Rng provides implementations of pseudo-random numbers generators.

SCXML - Implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine.

Validator - Framework to define validators and validation rules in an xml file.

VFS - Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.

Weaver - Provides an easy way to enhance (weave) compiled bytecode.

Projects

Other

CUBA Platform - High-level framework for developing enterprise applications with a rich web interface, based on Spring, EclipseLink and Vaadin.

Light-4Jstars3.4k - Fast, lightweight and productive microservices framework with built-in securitystars283.

Orienteerstars181 - Open-source business application platform for rapid configuration/development of CRM, ERP, LMS and other applications.

Spring - Provides many packages for dependency injection, aspect-oriented programming, security, etc.

Projects

Reactive libraries

Reactorstars4.2k - Library for building reactive fast-data applications.

Projects

REST Frameworks

Dropwizardstars8.2k - Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.

Elide - Opinionated framework for JSON- or GraphQL-APIs based on a JPA data model.

Microserverstars933 - 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.

RESTEasy - Fully certified and portable implementation of the JAX-RS specification.

Rapidoid - Simple, secure and extremely fast framework consisting of an embedded HTTP server, GUI components and dependency injection.

Projects

Science

DataMelt - Environment for scientific computation, data analysis and data visualization. (GPL-3.0-or-later)

JFreeChart - 2D chart library for Swing, JavaFX and server-side applications. (LGPL-2.1-only)

Morpheusstars219 - 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.

Tablesawstars2.9k - Includes a data-frame, an embedded column store, and hundreds of methods to transform, summarize, or filter data.

XChartstars1.3k - Light-weight library for plotting data. Many customizable chart types are available.

Projects

Search

Apache Solr - Enterprise search engine optimized for high-volume traffic.

Projects

Server

Jetty - Provides a Web server and javax.servlet container, plus support for HTTP/2, WebSocket, OSGi, JMX, JNDI, JAAS and many other integrations.

WildFly - Formerly known as JBoss and developed by Red Hat with extensive Java EE support. (LGPL-2.1-only)

Projects

Template Engine

Handlebars.java - Logicless and semantic Mustache templates.

Thymeleaf - Aims to be a substitute for JSP and works for XML files.

Projects

Asynchronous

Awaitilitystars3k - DSL for synchronizing asynchronous operations.

GreenMail - In-memory email server for integration testing. Supports SMTP, POP3 and IMAP including SSL. (GPL-2.0-only)

REST Assuredstars5.9k - DSL for easy testing of REST/HTTP services.

Projects

BDD

Cukes-RESTstars98 - Collection of Gherkin steps for REST-service testing using Cucumber.

JBehave - Extensively configurable framework that describes stories.

Serenity BDDstars633 - Automated Acceptance testing and reporting library that works with Cucumber, JBehave and JUnit to make it easier to write high quality executable specifications.

Projects

Frameworks

JUnit - Common testing framework.

Projects

Matchers

AssertJ - Fluent assertions that improve readability.

Hamcrest - Matchers that can be combined to create flexible expressions of intent.

Projects

Miscellaneous

pojo-tester - Automatically performs tests on basic POJO methods. (LGPL-3.0-only)

junit-dataproviderstars234 - TestNG-like data provider/runner for JUnit.

Projects

Mocking

PowerMockstars3.8k - Mocks static methods, constructors, final classes and methods, private methods, and removal of static initializers.

Projects

Utility

cactoosstars663 - Collection of object-oriented primitives.

Embulkstars1.6k - Bulk data loader that helps data transfer between various databases, storages, file formats, and cloud services.

JGit - Lightweight, pure Java library implementing the Git version control system.

fswatchstars21 - Micro library to watch for directory file system changes, simplifying java.nio.file.WatchService.

Projects

Version Managers

jenvstars4.3k - Java Version Manager inspired by rbenv. Can configure globally or per project. Tested on Debian and macOS.

jabbastars2.4k - Java Version Manager inspired by nvm. Supports macOS, Linux and Windows.

Projects

Web Frameworks

Bladestars5.6k - Lightweight, modular framework that aims to be elegant and simple.

Jooby - Scalable, fast and modular micro-framework that offers multiple programming models.

PrimeFaces - JSF framework with both free and commercial/support versions and frontend components.

Vaadin - Event-driven framework that uses standard web components. Server-side architecture with Ajax on the client side.

Resources

Communities

r/java - Subreddit for the Java community.

Stack Overflow - Question/answer platform.

Projects

Database

Modalitystars10 - Lightweight ORM with database reverse engineering features.

eXiststars349 - NoSQL document database and application platform. (LGPL-2.1-only)

Redissonstars19.3k - Allows for distributed and scalable data structures on top of a Redis server.

requerystars3.1k - 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.

Projects

Bean Mapping

JMapperstars194 - Uses byte code manipulation for lightning-fast mapping. Supports annotations and API or XML configuration.

ModelMapperstars2k - Intelligent object mapping library that automatically maps objects to each other.

Projects

Build

Bazel - Tool from Google that builds code quickly and reliably.

Projects

Bytecode Manipulation

ASM - All-purpose, low-level bytecode manipulation and analysis.

Byte Buddy - Further simplifies bytecode generation with a fluent API.

Javassiststars3.6k - Tries to simplify bytecode editing.

Projects

Caching

Infinispan - Highly concurrent key/value datastore used for caching.

Projects

CLI

JOpt Simple - Fluent parser that uses the POSIX#getopt and GNU#getopt_long syntaxes.

picocli - ANSI colors and styles in usage help with annotation-based POSIX/GNU/any syntax, subcommands, strong typing for both options and positional args.

Projects

Code Coverage

Clover - 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. (GPL-2.0-only)

JaCoCo - Framework that enables collection of code coverage metrics, using both offline and runtime bytecode instrumentation.

Projects

Code Generators

FreeBuilderstars796 - Automatically generates the Builder pattern.

Joda-Beans - Small framework that adds queryable properties to Java, enhancing JavaBeans.

Projects

Compiler-compiler

ANTLR - Complex full-featured framework for top-down parsing.

JavaCC - Parser generator that generates top-down parsers. Allows lexical state switching and permits extended BNF specifications.

JFlex - Lexical analyzer generator.

Projects

Configuration

dotenvstars41 - Twelve-factor configuration library which uses environment-specific files.

Projects

Constraint Satisfaction Problem Solver

Choco - Off-the-shelf constraint satisfaction problem solver that uses constraint programming techniques.

Projects

CSV

Super CSV - Powerful CSV parser with support for Dozer, Joda-Time and Java 8.

Projects

Data Structures

Apache Avro - Data interchange format with dynamic typing, untagged data, and 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 Google's paper on Dremel.

Apache Thrift - Data interchange format that originated at Facebook.

Big Queuestars503 - Fast and persistent queue based on memory-mapped files.

HyperMinHash-javastars47 - Probabilistic data structure for computing union, intersection, and set cardinality in loglog space.

Persistent Collectionstars692 - Persistent and immutable analogue of the Java Collections Framework.

Protobufstars55.1k - Google's data interchange format.

SBEstars2.7k - Simple Binary Encoding, one of the fastest message formats around.

Tapestars2.4k - Lightning-fast, transactional, file-based FIFO.

Wirestars3.8k - Clean, lightweight protocol buffers.

Projects

Date and Time

Almanac Converter - Simple conversion between different calendar systems.

Projects

Dependency Injection

Dagger - Compile-time injection framework without reflection.

HK2 - Lightweight and dynamic dependency injection framework.

Projects

Development

AspectJ - Seamless aspect-oriented programming extension.

JavaSymbolSolverstars286 - Symbol solver.

Manifoldstars1.3k - Re-energizes Java with powerful features like type-safe metaprogramming, structural typing and extension methods.

Projects

Distributed Transactions

Bitronixstars396 - Simple but complete implementation of the JTA 1.1 API.

Narayana - Provides support for traditional ACID and compensation transactions, also complies with JTA, JTS and other standards. (LGPL-2.1-only)

Projects

Distribution

Capsulestars1.1k - Simple and powerful packaging and deployment. A fat JAR on steroids, or a "Docker for Java" that supports JVM-optimized containers.

Nexus - Binary management with proxy and caching capabilities.

packrstars2.4k - Packs JARs, assets and the JVM for native distribution on Windows, Linux and macOS.

Projects

Document Processing

documents4j - API for document format conversion using third-party converters such as MS Word.

Projects

Financial

Squarestars38 - Integration with the Square API.

Stripestars610 - Integration with the Stripe API.

Projects

Formal Verification

Daikon - Detects likely program invariants and generates JML specs based on those invariants.

JMLOK 2.0 - Detects inconsistencies between code and JML specification through feedback-directed random tests generation, and suggests a likely cause for each nonconformance detected. (GPL-3.0-only)

KeY - 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. (GPL-2.0-or-later)

OpenJML - Translates JML specifications into SMT-LIB format and passes the proof problems implied by the program to backend solvers. (GPL-2.0-only)

Projects

Fixtures

Java Fakerstars3.6k - Port of Ruby's fake data generator.

Projects

Distribution

jlink.onlinestars1 - Builds optimized runtimes over HTTP.

Projects

Financial

Paritystars500 - Platform for trading venues.

Philadelphiastars267 - Low-latency financial information exchange.

Projects

Miscellaneous

yGuardstars222 - Obfuscation via renaming and shrinking.

Projects

Frameworks

jqwik - Engine for property-based testing built on JUnit 5.

Projects

REST Frameworks

springdoc-openapistars2k - Automates the generation of API documentation using Spring Boot projects.

Projects

Database

Leafstars5.4k - Distributed ID generate service.

Projects

Messaging

Apache RocketMQ - Fast, reliable, and scalable distributed messaging platform.

Projects

PaaS

Google Cloud - Google's cloud infrastructure.

OpenShift - Provides additionally an on-premise solution.

Projects

Job Scheduling

Quartzstars5.1k - Feature-rich, open source job scheduling library that can be integrated within virtually any Java application.

Sundialstars255 - Lightweight framework to simply define jobs, define triggers and start the scheduler.

Wispstars95 - Simple library with minimal footprint and straightforward API.

db-schedulerstars599 - Persistent and cluster-friendly scheduler.

Projects

Matchers

Truth - Google's fluent assertion and proposition framework.

Projects

CLI

Jexer - Advanced console (and Swing) text user interface (TUI) library, with mouse-draggable windows, built-in terminal window manager, and sixel image support. Looks like Turbo Vision.

Projects

PDF

OpenPDFstars2.4k - Open-source iText fork. (LGPL-3.0-only & MPL-2.0)

Resources

Twitter

Chris Richardson - Software architect, consultant, and serial entrepreneur, Java Champion, JavaOne Rock Star, *POJOs in Action- author.

Projects

JVM and JDK

Adopt Open JDK - Community-driven OpenJDK builds, including both HotSpot and OpenJ9.

Open JDK - Open JDK community home. (GPL-2.0-only WITH Classpath-exception-2.0)

Projects

Networking

ServiceTalkstars753 - Framework built on Netty with APIs tailored to specific protocols and support for multiple programming paradigms.

Projects

Database

druid - High-performance, column-oriented, distributed data store.

Projects

Introspection

Objenesis - Allows dynamic instantiation without default constructor, e.g. constructors which have required arguments, side effects or throw exceptions.

Resources

Twitter

Vlad Mihalcea - Java Champion working on Hypersistence Optimizer, database aficionado, author of High-Performance Java Persistence book.

Spencer Gibb - Software Engineer, Dad, Geek, Co-founder and Lead of Spring Cloud Core @pivotal.

Projects

IDE

jGRASP - Created to provide software visualizations that work in conjunction with the debugger such as Control Structure Diagrams, UML class diagrams and Object Viewer.

Projects

Bytecode Manipulation

Persesstars57 - Dynamically injects failure/latency at the bytecode level according to principles of chaos engineering.

Projects

Bean Mapping

reMapstars97 - Lambda and method handle-based mapping which requires code and not annotations if objects have different names.

Projects

Introspection

ClassGraphstars2.2k - ClassGraph (formerly FastClasspathScanner) is an uber-fast, ultra-lightweight, parallelized classpath scanner and module scanner for Java, Scala, Kotlin and other JVM languages.

ReflectASMstars1.3k - ReflectASM is a very small Java library that provides high performance reflection by using code generation.

Reflectionsstars4.2k - Reflections scans your classpath, indexes the metadata, allows you to query it on runtime and may save and collect that information for many modules within your project.

Projects

Matchers

XMLUnitstars266 - Simplifies testing for XML output.

Projects

Distribution

Boxfuse - Deployment of JVM applications to AWS using the principles of immutable infrastructure.

Projects

Bytecode Manipulation

bytecode-viewerstars13k - Java 8 Jar & Android APK reverse engineering suite. (GPL-3.0-only)

Byteman - Manipulate bytecode at runtime via DSL (rules); mainly for testing/troubleshooting. (LGPL-2.1-or-later)

Projects

CLI

Lanternastars1.9k - Easy console text-GUI library, similar to curses. (LGPL-3.0-only)

Projects

Code Analysis

Checkstylestars7.1k - Static analysis of coding conventions and standards. (LGPL-2.1-or-later)

jQAssistant - Static code analysis with Neo4J-based query language. (GPL-3.0-only)

SonarJavastars905 - Static analyzer for SonarQube & SonarLint. (LGPL-3.0-only)

Spotbugsstars2.7k - Static analysis of bytecode to find potential bugs. (LGPL-2.1-only)

Projects

Constraint Satisfaction Problem Solver

JaCoPstars191 - Includes an interface for the FlatZinc language, enabling it to execute MiniZinc models. (AGPL-3.0)

Projects

Date and Time

Time4Jstars371 - Advanced date and time library. (LGPL-2.1-only)

Projects

Dependency Injection

JayWirestars50 - Lightweight dependency injection framework. (LGPL-3.0-only)

Projects

Development

DCEVM - JVM modification that allows unlimited redefinition of loaded classes at runtime. (GPL-2.0-only)

HotswapAgentstars1.8k - Unlimited runtime class and resource redefinition. (GPL-2.0-only)

Projects

Distributed Applications

Dropwizard Circuit Breakerstars41 - Circuit breaker design pattern for Dropwizard. (GPL-2.0-only)

Atomix - Fault-tolerant distributed coordination framework.

Projects

Formal Verification

Checker Framework - Pluggable type systems. Includes nullness types, physical units, immutability types and more. (GPL-2.0-only WITH Classpath-exception-2.0)

Java Path Finder (JPF)stars388 - JVM formal verification tool containing a model checker and more. Created by NASA.

Projects

Functional Programming

derive4jstars541 - Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching and morphisms. (GPL-3.0-only)

Projects

Geospatial

GeoTools - Library that provides tools for geospatial data. (LGPL-2.1-only)

Mapsforgestars974 - Map rendering based on OpenStreetMap data. (LGPL-3.0-only)

Projects

JVM and JDK

Graalstars17.2k - Polyglot embeddable JVM. (GPL-2.0-only WITH Classpath-exception-2.0)

ParparVM - VM with non-blocking, concurrent GC for iOS. (GPL-2.0-only WITH Classpath-exception-2.0)

RedHat Open JDK - RedHat's OpenJDK distribution. (GPL-2.0-only WITH Classpath-exception-2.0)

Projects

Logging

Graylog - Open-source aggregator suited for extended role and permission management. (GPL-3.0-only)

Projects

Machine Learning

JSATstars739 - Algorithms for pre-processing, classification, regression, and clustering with support for multi-threaded execution. (GPL-3.0-only)

Projects

Miscellaneous

FizzBuzz Enterprise Editionstars17.5k - No-nonsense implementation of FizzBuzz made by serious businessmen for serious business purposes. (No explicit license)

Projects

Natural Language Processing

CogCompNLP