Projects

• API Compatibility
• Architecture
• Artificial Intelligence
• Bean Mapping
• Bot Development
• Build
• Bytecode Manipulation
• Caching
• CLI
• Cloud
• Code Analysis
• Code Coverage
• Code Formatting
• Code Generators
• Compiler-compiler
• Computer Vision
• Configuration
• Constraint Satisfaction Problem Solver
• CSV
• Data Processing
• Data Structures
• Database
• Date and Time
• Decentralization
• Decompilation
• Dependency Injection
• Development
• Distributed Applications
• Distributed Transactions
• Distribution
• Document Processing
• Feature Flags
• Financial
• Flat File
• Formal Verification
• Functional Programming
• Game Development
• Geospatial
• GUI
• High Performance
• HTTP Clients
• IDE
• Imagery
• Introspection
• Job Scheduling
• JSON
• JVM and JDK
• Logging
• Machine Learning
• Messaging
• Microservice
• Miscellaneous
• Mobile Development
• Monitoring
• Native
• Natural Language Processing
• Networking
• ORM
• PaaS
• PDF
• Performance analysis
• Platform
• Processes
• Proxy Servers
• Reactive libraries
• Regular Expressions
• REST Frameworks
• Science
• Scripting
• Search
• Security
• Serialization
• Server
• Spreadsheet
• Template Engine
• Testing
• Utility
• Version Managers
• Web Crawling
• Web Frameworks
• Workflow Orchestration Engines

Resources

• Related Awesome Lists
• Communities
• Guides and References
• Influential Books
• Podcasts and Screencasts
• People
• Websites

Tools for tracking API evolution and detecting breaking changes between library versions.

japicmp ★ 779 Apache-2.0 🟢
Compares two library JARs and reports source- and binary-incompatible changes.

Revapi ★ 223 Apache-2.0 🟠
Extensible API analysis and change tracking with configurable source, binary and semantic compatibility checks.

Roseau ★ 41 MIT 🟢
Detects source- and binary-breaking changes by comparing library versions from JAR files or source code.

Frameworks and libraries that help implementing and verifying design and architecture concepts.

ArchUnit ★ 3.8k Apache-2.0 🟢
Test library for specifying and asserting architecture rules.

jMolecules ★ 1.6k Apache-2.0 🟠
Annotations and interfaces to express design and architecture concepts in code.

jQAssistant ★ 292 GPL-3.0 🟢
Static code analysis with Neo4J-based query language.

Taikai ★ 256 MIT 🟢
ArchUnit extension with predefined architecture rules for common Java technologies.

WireDoctor ★ 8 Apache-2.0 🟢
Runtime diagnostic for Spring Boot apps that detects cyclic bean dependencies and slow beans, with CI regression gates.

Frameworks for building applications with AI, agents and knowledge-based systems.

A2A Java SDK ★ 496 Apache-2.0 🟢
Official Java SDK for the Agent2Agent protocol.

AgentScope Java ★ 5.7k Apache-2.0 🟢
Framework for building distributed, long-running AI agents with tool execution, persistence and multi-agent orchestration.

Anahata ASI ★ 27 Apache-2.0 🟢
Java agent container with local LLM adapters, stateful tool execution, context management and IDE integration.

ARA ★ 6 Apache-2.0 🟢
Java framework for AI agents with tool calling, deterministic input and output contracts, and configurable execution strategies.

Dokimos ★ 58 MIT 🟢
Evaluation framework for LLM and AI-agent applications that scores responses, validates tool calls and execution traces, and catches quality regressions in CI.

Google Gen AI Java SDK ★ 397 Apache-2.0 🟢
Official Java SDK for integrating Google generative AI models.

JADE
Framework and environment for building and debugging multi-agent systems. (LGPL-2.0-only)

JamJet ★ 21 Apache-2.0 🟢
Agent runtime with a Java SDK for building AI agents, supporting graph-based workflow orchestration, multi-agent coordination, and MCP/A2A protocols.

LangChain4j ★ 13.1k Apache-2.0 🟢
Simplifies integration of LLMs with unified APIs and a comprehensive toolbox.

liter-llm ★ 255 MIT 🟢
Provides a Java binding for a unified LLM API client across multiple providers.

MCP Java SDK ★ 3.7k MIT 🟢
Enables applications to interact with AI models and tools through a standardized interface (i.e. Model Context Protocol), supporting both synchronous and asynchronous communication patterns.

Protégé ★ 1.5k 🟠
Provides an ontology editor and a framework to build knowledge-based systems.

Regulus ★ 6 MIT 🟢
Google ADK plugin suite that adds runtime compliance profiles, audit envelopes and GRC adapters for regulated Java AI agents.

simple-openai ★ 382 MIT 🔴
Library to use the OpenAI API (and compatible ones) in the simplest possible way.

Spring AI ★ 9.5k Apache-2.0 🟢
Application framework for AI engineering for Spring.

Spring AI Alibaba ★ 10.9k Apache-2.0 🟢
Agentic AI framework built on Spring AI with model, tool, RAG and workflow integrations.

Frameworks that ease bean mapping.

Immuto ★ 6 🟢
Annotation processor that generates type-safe mapper implementations for Java Records using canonical constructors, with zero runtime reflection.

MapStruct ★ 7.7k 🟢
Code generator that simplifies mappings between different bean types, based on a convention-over-configuration approach.

ModelMapper ★ 2.4k Apache-2.0 🟠
Intelligent object mapping library that automatically maps objects to each other.

reMap ★ 128 Apache-2.0 🟢
Lambda and method handle-based mapping which requires code and not annotations if objects have different names.

Libraries and frameworks for building chatbots and messaging-platform bots.

JBot ★ 1.2k GPL-3.0 🟠
Framework for building chatbots.

JDA ★ 4.7k Apache-2.0 🟢
Wrapping of the Discord REST API and its WebSocket events.

Nyagram ★ 9 MIT 🟢
Reactive, type-safe framework for Telegram bots based on Spring Boot 3 and Java 21.

TelegramBots ★ 5.5k MIT 🟢
Java library for building bots with the Telegram Bot API.

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

Apache Maven ★ 5.4k Apache-2.0 🟢
Declarative build and dependency management that favors convention over configuration. It might be preferable to Apache Ant, which uses a rather procedural approach and can be difficult to maintain.

Bazel ★ 25.9k Apache-2.0 🟢
Tool from Google that builds code quickly and reliably.

Buck2 ★ 4.4k Apache-2.0 🟢
Encourages the creation of small, reusable modules consisting of code and resources.

Dependency Analysis Gradle Plugin ★ 2.2k Apache-2.0 🟢
Analyzes JVM and Android builds and recommends dependency and plugin changes.

Docker Maven Plugin ★ 1.9k Apache-2.0 🟢
Builds and runs Docker images from Maven.

Eclipse JKube ★ 852 EPL-2.0 🟢
Maven and Gradle plugins for building and deploying Java applications on Kubernetes.

Frontend Maven Plugin ★ 4.4k Apache-2.0 🟢
Installs and runs Node.js frontend tooling from Maven builds.

git-commit-id Maven Plugin ★ 1.7k LGPL-3.0 🟢
Exposes Git revision information to Maven builds and applications.

Gradle ★ 18.8k Apache-2.0 🟢
Incremental builds programmed via Groovy instead of declaring XML. Works well with Maven's dependency management.

jar-cart ★ 4 MIT 🟢
A modern, zero-configuration package manager and runner for the Java ecosystem written in Go, focusing on developer productivity and build speed.

Javadoc Publisher ★ 58 Apache-2.0 🟠
Generate Javadoc from your maven/gradle project and deploy it automatically on GitHub Page.

Jib ★ 14.5k Apache-2.0 🟢
Builds optimized container images for Java applications without a Docker daemon.

Maven Wrapper ★ 254 Apache-2.0 🟢
Analogue of Gradle Wrapper for Maven, allowing projects to build without a preinstalled Maven.

Polyglot for Maven ★ 919 EPL-1.0 🟢
Extensions for Maven 3.3.1+ that allows writing the POM model in dialects other than XML.

ReleaseRun ★ 1 MIT 🟠
Dependency health checker for pom.xml and Gradle projects that scans for CVEs and outdated packages.

Shadow ★ 4.2k Apache-2.0 🟢
Gradle plugin for creating and transforming executable fat JARs.

Libraries to manipulate bytecode programmatically.

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

Byte Buddy ★ 6.9k Apache-2.0 🟢
Further simplifies bytecode generation with a fluent API.

bytecode-viewer ★ 15.7k GPL-3.0 🟢
Java 8 Jar & Android APK reverse engineering suite.

Byteman ★ 515 🟢
Manipulate bytecode at runtime via DSL (rules); mainly for testing/troubleshooting. (LGPL-2.1-or-later)

Javassist ★ 4.2k 🟢
Tries to simplify bytecode editing.

Maker ★ 73 Apache-2.0 🟢
Provides low level bytecode generation.

Recaf ★ 7.4k MIT 🟢
JVM reverse engineering toolkit, essentially an IDE for Java bytecode.

Libraries that provide caching facilities.

cache2k ★ 743 Apache-2.0 🔴
In-memory high performance caching library.

Caffeine ★ 17.9k Apache-2.0 🟢
High-performance, near-optimal caching library.

Ehcache ★ 2.1k Apache-2.0 🟢
Distributed general-purpose cache.

Infinispan ★ 1.4k Apache-2.0 🟢
Highly concurrent key/value datastore used for caching.

JetCache ★ 5.6k Apache-2.0 🟢
Java cache framework with local and distributed caching, annotations and asynchronous APIs.

Libraries for everything related to the CLI.

Libraries to assist with parsing command line arguments.

Airline ★ 145 Apache-2.0 🟢
Annotation-based framework for parsing Git-like command-line arguments.

jbock ★ 94 MIT 🟢
Reflectionless command line parser.

JCommander ★ 2.0k Apache-2.0 🟢
Command-line argument-parsing framework with custom types and validation via implementing interfaces.

JLine ★ 1.8k 🟢
Includes features from modern shells like completion or history.

picocli ★ 5.4k Apache-2.0 🟢
ANSI colors and styles in usage help with annotation-based POSIX/GNU/any syntax, subcommands, strong typing for both options and positional args.

Libraries that provide TUI frameworks, or building blocks related functions.

AliveJTUI ★ 9 🟠
Declarative, React-style TUI library for building terminal UIs as component trees with diff-based rendering, focus management, and themes.

Jansi ★ 1.2k Apache-2.0 🟠
ANSI escape codes to format console output.

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.

Lanterna ★ 2.6k LGPL-3.0 🟢
Easy console text-GUI library, similar to curses.

Libraries to integrate or use cloud-specific features.

AWS SDK for Java 2.x ★ 2.6k Apache-2.0 🟢
Official Java APIs for interacting with Amazon Web Services.

Google Cloud Client Libraries ★ 2.1k Apache-2.0 🟢
Client libraries for accessing Google Cloud services from Java applications.

Java Operator SDK ★ 944 Apache-2.0 🟢
SDK for implementing Kubernetes operators in Java.

Kubernetes Java Client ★ 4.0k Apache-2.0 🟢
Official Java client for the Kubernetes API.

kubernetes-client ★ 3.7k Apache-2.0 🟢
Client provides access to the full Kubernetes & OpenShift REST APIs via a fluent DSL.

minio-java ★ 1.3k Apache-2.0 🟢
Provides simple APIs to access any Amazon S3-compatible object storage server.

Tools that provide metrics and quality measurements.

Checkstyle ★ 9.6k LGPL-2.1 🟢
Static analysis of coding conventions and standards.

Error Prone ★ 7.2k Apache-2.0 🟢
Catches common programming mistakes as compile-time errors.

Error Prone Support ★ 39 MIT 🟢
Error Prone extensions: extra bug checkers and a large battery of Refaster templates.

Infer ★ 15.7k MIT 🟢
Modern static analysis tool for verifying the correctness of code.

JSpecify ★ 1.1k Apache-2.0 🟢
Standardized nullness annotations designed to work uniformly across various Java IDEs, compilers, and static analysis tools.

Modernizer ★ 392 Apache-2.0 🟢
Detect uses of legacy Java APIs.

Mutability Detector ★ 247 Apache-2.0 🟠
Reports whether instances of a given class are immutable.

NullAway ★ 4.1k MIT 🟢
Eliminates NullPointerExceptions with low build-time overhead.

OpenRewrite ★ 3.7k Apache-2.0 🟢
Automates large-scale source-code refactoring through reusable recipes.

OpenTaint ★ 158 Apache-2.0 🟢
Interprocedural taint analyzer for Java and Spring applications with reusable security rules and dependency models.

PMD ★ 5.5k 🟢
Source code analysis for finding bad coding practices.

RealDiff ★ 35 MIT 🟢
Compares runtime method arguments and return values across Git revisions by running existing Maven or Gradle tests.

RefactorFirst ★ 548 Apache-2.0 🟢
Identifies and prioritizes God Classes and Highly Coupled classes.

SonarJava ★ 1.2k 🟢
Static analyzer for SonarQube & SonarLint. (LGPL-3.0-only)

Spoon ★ 2.0k 🟢
Library for analyzing and transforming Java source code.

Spotbugs ★ 3.9k LGPL-2.1 🟢
Static analysis of bytecode to find potential bugs.

ToolsHref ★ 0 🟠
Online Java code analyzer and JSON-to-Mermaid visualization tool.

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

Delta Coverage ★ 41 MIT 🟢
Computes code coverage of new and modified code based on a provided diff, supporting JaCoCo and IntelliJ coverage engines.

JaCoCo ★ 4.6k 🟢
Framework that enables collection of code coverage metrics, using both offline and runtime bytecode instrumentation.

OpenClover ★ 70 🟢
Measures Java code coverage through source-code instrumentation, with build-tool and IDE integrations.

Supercov ★ 107 MIT 🟢
Measures line, branch, and MC/DC coverage of Java and Kotlin test runs and scores source files for code quality.

Tools that format or restructure Java source code.

google-java-format ★ 6.2k 🟢
Reformats Java source code to follow Google Java Style.

JHarmonizer ★ 30 🟢
Safely reorders Java source code with configurable rules and Palantir Java Format.

Palantir Java Format ★ 909 Apache-2.0 🟢
Formatter based on google-java-format with wider lines and lambda-friendly output.

Spotless ★ 5.7k Apache-2.0 🟢
A versatile code formatter for Gradle and Maven that enforces multiple styles (including Google and Palantir) across Java and other languages.

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

Auto ★ 10.6k Apache-2.0 🟢
Generates factory, service, and value classes.

Avaje HTTP ★ 96 Apache-2.0 🟢
Generates HTTP server adapters and declarative clients, with a lightweight JDK HTTP client.

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

Chocotea ★ 47 Apache-2.0 🔴
Generates postman collection, environment and integration tests from java code.

CRUDGen ★ 12 Apache-2.0 🟠
Compile-time annotation processor generating CRUD layers, DTOs, JSON Patch, and custom HTTP endpoints for Spring Boot.

DevOpsForge ★ 0 MIT 🟢
Visual generator for Spring Boot Dockerfiles and Docker Compose configurations.

EasyEntityToDTO ★ 11 MIT 🟠
Annotation processor for automatic DTO and Mapper generation with zero boilerplate.

Geci ★ 139 Apache-2.0 🟠
Discovers files that need generated code, updates automatically and writes to the source with a convenient API.

Immutables ★ 3.6k Apache-2.0 🟢
Annotation processors to generate simple, safe and consistent value objects.

J2ObjC ★ 6.0k 🟢
Java-to-Objective-C translator for porting Android libraries to iOS.

JHipster ★ 22.5k Apache-2.0 🟢
Yeoman source code generator for Spring Boot and AngularJS.

Joda-Beans ★ 151 Apache-2.0 🔴
Small framework that adds queryable properties to Java, enhancing JavaBeans.

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.

jsonschema2pojo ★ 6.4k Apache-2.0 🟠
Generates Java types from JSON Schema or example JSON.

JSpecify Package-Info Generator ★ 4 Apache-2.0 🟠
Maven plugin that automatically generates package-info.java files with JSpecify annotations (@NullMarked and @NullUnmarked), helping you manage nullness boundaries in your Java projects without manual boilerplate.

Lombok ★ 13.5k 🟢
Code generator that aims to reduce verbosity.

Record-Builder ★ 929 Apache-2.0 🟢
Companion builder class, withers and templates for Java records.

Spring CRUD Generator ★ 39 Apache-2.0 🟢
Maven plugin for generating Spring Boot CRUD applications from YAML/JSON specifications.

SpringBoot Generator
Browser-based generator producing a Spring Boot CRUD REST API and an optional Angular or React frontend as separately deployable projects, including n-ary association entities. Commercial with a free tier.

Telosys ★ 214 LGPL-3.0 🟠
Java code-generation toolkit with a CLI and model-driven template engine.

Frameworks that help to create parsers, interpreters or compilers.

ANTLR ★ 19.0k BSD-3-Clause 🟠
Complex full-featured framework for top-down parsing.

JavaCC ★ 1.3k BSD-3-Clause 🔴
Parser generator that generates top-down parsers. Allows lexical state switching and permits extended BNF specifications.

JFlex ★ 634 🔴
Lexical analyzer generator.

Libraries which seek to gain high level information from images and videos.

BoofCV ★ 1.2k 🟢
Library for image processing, camera calibration, tracking, SFM, MVS, 3D vision, QR Code and much more.

ImageJ ★ 786 🟢
Medical image processing application with an API.

JavaCV ★ 8.3k 🟢
Java interface to OpenCV, FFmpeg, and much more.

Libraries that provide external configuration.

avaje config ★ 109 Apache-2.0 🟢
Loads yaml and properties files, supports dynamic configuration, plugins, file-watching and config event listeners.

centraldogma ★ 668 Apache-2.0 🟢
Highly-available version-controlled service configuration repository based on Git, ZooKeeper and HTTP/2.

ClearConfig ★ 10 Apache-2.0 🟢
Type-safe, composable configuration library with a focus on runtime clarity.

config ★ 6.3k 🟢
Configuration library supporting Java properties, JSON or its human optimized superset HOCON.

Configurate ★ 465 Apache-2.0 🟢
Configuration library with support for various configuration formats and transformations.

dotenv ★ 51 🔴
Twelve-factor configuration library which uses environment-specific files.

Externalized Properties ★ 48 Apache-2.0 🟢
Simple, lightweight, yet powerful configuration library which supports resolution of properties from external sources such as files, databases, git repositories, and any custom sources, plus an extensible post-processing/conversion mechanism.

Gestalt ★ 104 Apache-2.0 🟢
Gestalt offers a comprehensive solution to the challenges of configuration management. It allows you to source configuration data from multiple inputs, merge them intelligently, and present them in a structured, type-safe manner.

ini4j
Provides an API for handling Windows' INI files.

KAConf ★ 62 Apache-2.0 🔴
Annotation-based configuration system for Java and Kotlin.

microconfig ★ 320 Apache-2.0 🔴
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.

NightConfig ★ 287 LGPL-3.0 🟢
Configuration library supporting TOML, YAML, HOCON, JSON and in-memory formats.

owner ★ 940 BSD-3-Clause 🟢
Reduces boilerplate of properties.

sealed-env ★ 9 MIT 🟢
Encrypts environment files with a shared Node.js and Java/Spring Boot format plus optional TOTP unsealing.

Libraries that help with implementing optimization and satisfiability problems.

Choco ★ 779 BSD-3-Clause 🟢
Off-the-shelf constraint satisfaction problem solver that uses constraint programming techniques.

JaCoP ★ 235 🟠
Includes an interface for the FlatZinc language, enabling it to execute MiniZinc models. (AGPL-3.0)

Timefold ★ 1.8k Apache-2.0 🟢
Flexible solver with Spring/Quarkus support and quickstarts for the Vehicle Routing Problem, Maintenance Scheduling, Employee Shift Scheduling and much more.

Frameworks and libraries that simplify reading/writing CSV data.

FastCSV ★ 692 MIT 🟢
Performance-optimized, dependency-free and RFC 4180 compliant.

jackson-dataformat-csv ★ 455 Apache-2.0 🟢
Jackson extension for reading and writing CSV.

opencsv
Simple CSV parser.

Tools for batch, stream, table and data-transformation workloads.

Apache Flink ★ 26.3k Apache-2.0 🟢
Fast, reliable, large-scale data processing engine.

Apache Storm ★ 6.7k Apache-2.0 🟢
Realtime computation system.

easy-batch ★ 622 MIT 🔴
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.

Embulk ★ 1.8k Apache-2.0 🟠
Bulk data loader that helps data transfer between various databases, storages, file formats, and cloud services.

OpenRefine ★ 12.0k BSD-3-Clause 🟢
Tool for working with messy data: cleaning, transforming, extending it with web services and linking it to databases.

Scriptella ETL ★ 125 Apache-2.0 🟢
Open-source Java-based ETL and script execution tool for transferring and transforming data between databases, files, and other sources.

Siddhi ★ 1.6k Apache-2.0 🟠
Cloud native streaming and complex event processing engine.

Smooks ★ 420 🟠
Framework for fragment-based message processing. (Apache-2.0 OR LGPL-3.0-or-later)

Tablesaw ★ 3.8k Apache-2.0 🟢
Includes a data-frame, an embedded column store, and hundreds of methods to transform, summarize, or filter data.

Efficient and specific data structures.

CQEngine Next ★ 19 Apache-2.0 🟢
Provides indexed, SQL-like queries over Java collections.

HashSmith ★ 108 MIT 🟢
Hash map and set implementations using SwissTable-style SWAR/SIMD control-byte probing, optimized for memory efficiency.

Persistent Collection ★ 791 🔴
Persistent and immutable analogue of the Java Collections Framework.

RoaringBitmap ★ 3.9k Apache-2.0 🟢
Fast and efficient compressed bitmap.

Wormhole4j ★ 10 Apache-2.0 🟠
High-performance sorted map with fast range scans and thread-safe concurrent access, based on the Wormhole index structure.

Everything that simplifies interactions with the database.

Actual Schema Gradle Plugin ★ 18 Apache-2.0 🟢
Generates PostgreSQL schema DDL from Liquibase migrations using Testcontainers.

Apache Calcite ★ 5.2k Apache-2.0 🟢
Dynamic data management framework. It contains many of the pieces that comprise a typical database management system.

Apache Cassandra ★ 10.1k Apache-2.0 🟢
Distributed wide-column database with linear scalability and fault tolerance.

Apache Doris ★ 16.0k Apache-2.0 🟢
Distributed SQL database for real-time analytics.

Apache Drill ★ 2.0k Apache-2.0 🟢
Distributed, schema on-the-fly, ANSI SQL query engine for Big Data exploration.

Apache Phoenix ★ 1.1k Apache-2.0 🟢
High-performance relational database layer over HBase for low-latency applications.

Apache ShardingSphere ★ 20.8k Apache-2.0 🟢
Distributed SQL transaction & query engine that allows for data sharding, scaling, encryption, and more on any database.

ArangoDB ★ 210 Apache-2.0 🟢
ArangoDB Java driver.

ArcadeDB ★ 1.2k Apache-2.0 🟢
Multi-model database supporting graphs, documents, key-value, time series, and vector embeddings with SQL, Cypher, Gremlin, MongoDB, and Redis API compatibility.

Chronicle Map ★ 3.0k Apache-2.0 🟢
Efficient, in-memory (opt. persisted to disk), off-heap key-value store.

ClickHouse Java ★ 1.6k Apache-2.0 🟢
Java clients and JDBC driver for ClickHouse.

CosId ★ 648 Apache-2.0 🟢
Universal, flexible, high-performance distributed ID generator.

Debezium ★ 13.1k Apache-2.0 🟢
Low latency data streaming platform for change data capture.

druid ★ 14.1k Apache-2.0 🟢
High-performance, column-oriented, distributed data store.

eXist ★ 470 LGPL-2.1 🟢
NoSQL document database and application platform.

FlexyPool ★ 1.2k Apache-2.0 🟠
Brings metrics and failover strategies to the most common connection pooling solutions.

Flyway ★ 10.1k Apache-2.0 🟢
Simple database migration tool.

H2 ★ 4.6k 🟢
Small SQL database notable for its in-memory functionality.

HikariCP ★ 21.2k Apache-2.0 🟠
High-performance JDBC connection pool.

HSQLDB
HyperSQL 100% Java database.

JanusGraph ★ 5.8k 🟢
Distributed graph database supporting pluggable storage and indexing backends.

JDBI ★ 2.1k Apache-2.0 🟢
Convenient abstraction of JDBC.

Jedis ★ 12.4k MIT 🟢
Java client for Redis with synchronous, asynchronous and cluster APIs.

jetcd ★ 1.2k Apache-2.0 🟢
Java client for etcd v3.

Jinq ★ 661 🔴
Typesafe database queries via symbolic execution of Java 8 Lambdas (on top of JPA or jOOQ).

jOOQ ★ 6.8k 🟢
Generates typesafe code based on SQL schema.

JQuick SQL ★ 242 🟢
Embeddable, lightweight distributed SQL engine featuring heterogeneous federated query support for unified data access across disparate systems.

Lettuce ★ 5.8k MIT 🟢
Lettuce is a scalable Redis client for building non-blocking Reactive applications.

Liquibase ★ 5.6k 🟢
Database-independent library for tracking, managing and applying database schema changes.

MapDB ★ 5.1k Apache-2.0 🟢
Embedded database engine that provides concurrent collections backed on disk or in off-heap memory.

MariaDB4j ★ 17 Apache-2.0 🟢
Launcher for MariaDB that requires no installation or external dependencies.

Modality ★ 17 Apache-2.0 🟢
Lightweight ORM with database reverse engineering features.

MongoDB Java Driver ★ 2.7k Apache-2.0 🟢
Official synchronous, asynchronous and reactive Java drivers for MongoDB.

ObjectBox ★ 4.6k Apache-2.0 🟢
Embedded object and vector database for Java and Android.

Open J Proxy ★ 227 Apache-2.0 🟢
Type 3 JDBC driver and Layer 7 proxy server for decoupling applications from relational database connection management.

OpenDJ ★ 439 🟢
LDAPv3 compliant directory service, developed for the Java platform, providing a high performance, highly available, and secure store for the identities.

Presto ★ 16.7k Apache-2.0 🟢
Distributed SQL query engine for large data sources.

Querydsl ★ 5.0k Apache-2.0 🟠
Typesafe unified queries.

QueryStream ★ 22 Apache-2.0 🔴
Build JPA Criteria queries using a Stream-like API.

QuestDB ★ 17.3k Apache-2.0 🟢
High-performance SQL database for time series. Supports InfluxDB line protocol, PostgreSQL wire protocol, and REST.

Realm ★ 11.5k Apache-2.0 🔴
Mobile database to run directly inside phones, tablets or wearables.

Redisson ★ 24.4k Apache-2.0 🟢
Allows for distributed and scalable data structures on top of a Redis server.

requery ★ 3.1k Apache-2.0 🟠
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.

SchemaCrawler ★ 1.8k 🟢
Discovers, documents and diagrams relational database schemas from Java, build tools and the command line.

Spring Data Dynamic Query ★ 39 Apache-2.0 🟠
Unified dynamic query interface for Spring Data JPA, MongoDB, and Elasticsearch, enabling advanced JOIN(s), OR logic, scoped conditions, powerful projections and advanced features with zero boilerplate.

Spring Data JPA MongoDB Expressions ★ 107 Apache-2.0 🟠
Allows you to use MongoDB query language to query your relational database.

StarRocks ★ 12.1k Apache-2.0 🟢
Distributed SQL query engine for real-time analytics and data lakehouses.

Trino ★ 13.3k Apache-2.0 🟢
Distributed SQL query engine for big data.

Vibur DBCP ★ 124 Apache-2.0 🔴
JDBC connection pool library with advanced performance monitoring capabilities.

Xodus ★ 1.3k Apache-2.0 🟢
Highly concurrent transactional schema-less and ACID-compliant embedded database.

Libraries related to handling date and time.

iCal4j ★ 837 BSD-3-Clause 🟢
Parse and build iCalendar RFC 5545 data models.

Jollyday ★ 138 Apache-2.0 🟢
Determines the holidays for a given year, country/name and eventually state/region.

ThreeTen-Extra ★ 426 BSD-3-Clause 🟢
Additional date-time classes that complement those in JDK 8.

Time4J ★ 473 LGPL-2.1 🔴
Advanced date and time library.

Libraries that handle decentralization tasks.

bitcoinj ★ 5.2k Apache-2.0 🟢
Library for working with the Bitcoin protocol and network.

java-tron ★ 4.2k LGPL-3.0 🟢
Implementation of the Tron Protocol, whic utilizes blockchains to develop decentralized applications.

web3j ★ 5.4k 🟢
Java and Android library for integrating with Ethereum-compatible blockchains.

Libraries for decompiling JVM bytecode.

CFR ★ 2.7k MIT 🟠
Java decompiler focused on modern language features.

Fernflower ★ 4.4k Apache-2.0 🟢
Java decompiler with broad JVM bytecode support.

jadx ★ 50.5k Apache-2.0 🟢
Dex-to-Java decompiler with command-line and graphical interfaces.

transformer-api ★ 3 Apache-2.0 🟢
Unified API that exposes multiple decompilers through one in-memory transformation interface.

Vineflower ★ 2.4k Apache-2.0 🟢
Modern maintained fork of Fernflower.

Libraries that help to realize the Inversion of Control paradigm.

Apache DeltaSpike ★ 154 Apache-2.0 🟢
CDI extension framework.

Avaje Inject ★ 317 Apache-2.0 🟢
Microservice-focused compile-time injection framework without reflection.

Dagger ★ 17.7k Apache-2.0 🟢
Compile-time injection framework without reflection.

Dimension-DI ★ 20 Apache-2.0 🟢
JSR-330 runtime dependency injection using the JDK Class-File API.

Governator ★ 829 Apache-2.0 🟠
Extensions and utilities that enhance Google Guice.

Guice ★ 12.7k Apache-2.0 🟢
Lightweight and opinionated framework that completes Dagger.

HK2 ★ 94 🟢
Lightweight and dynamic dependency injection framework.

Augmentation of the development process at a fundamental level.

AspectJ ★ 394 🟠
Seamless aspect-oriented programming extension.

Faux Pas ★ 144 MIT 🔴
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.

Ghidra ★ 79.2k Apache-2.0 🟢
Extensible software reverse-engineering framework with Java APIs and scripting.

HotswapAgent ★ 2.6k GPL-2.0 🟢
Unlimited runtime class and resource redefinition.

JavaParser ★ 6.2k 🟢
Parse, modify and generate Java code.

Jctx ★ 6 MIT 🟠
Reads a Java project and generates a structured context file so AI tools can understand and help plan the codebase.

JGit ★ 426 🟢
Lightweight, pure Java library implementing the Git version control system.

Manifold ★ 2.8k Apache-2.0 🟢
Re-energizes Java with powerful features like type-safe metaprogramming, structural typing and extension methods.

NoException ★ 131 Apache-2.0 🔴
Allows checked exceptions in functional interfaces and converts exceptions to Optional return.

RR4J ★ 26 GPL-3.0 🔴
RR4J is a tool that records java bytecode execution and later allows developers to replay locally.

SneakyThrow ★ 81 MIT 🔴
Ignores checked exceptions without bytecode manipulation. Can also be used inside Java 8 stream operations.

Tail ★ 31 Unlicense 🔴
Enable infinite recursion using tail call optimization.

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

Apache Geode ★ 2.4k Apache-2.0 🟢
In-memory data management system that provides reliable asynchronous event notifications and guaranteed message delivery.

Apache ZooKeeper ★ 12.8k Apache-2.0 🟢
Coordination service with distributed configuration, synchronization, and naming registry for large distributed systems.

Axon ★ 3.6k Apache-2.0 🟢
Framework for creating CQRS applications.

Curator Framework ★ 3.2k Apache-2.0 🟢
High-level API for Apache ZooKeeper.

Dropwizard Circuit Breaker ★ 46 GPL-2.0 🟠
Circuit breaker design pattern for Dropwizard.

Failsafe ★ 4.3k Apache-2.0 🟠
Simple failure handling with retries and circuit breakers.

Fuse ★ 2 Apache-2.0 🟢
Circuit breaker for Java microservices with zero runtime dependencies and lock-free CAS.

Hazelcast ★ 6.6k 🟢
Highly scalable in-memory datagrid with a free open-source version.

JGroups ★ 1.1k Apache-2.0 🟢
Toolkit for reliable messaging and cluster creation.

resilience4j ★ 10.8k Apache-2.0 🟢
Functional fault tolerance library.

ScaleCube Services ★ 638 Apache-2.0 🟢
Embeddable Cluster-Membership library based on SWIM and gossip protocol.

Distributed transactions provide a mechanism for ensuring consistency of data updates in the presence of concurrent access and partial failures.

Atomikos ★ 486 🟢
Provides transactions for REST, SOA and microservices with support for JTA and XA.

Bitronix ★ 431 Apache-2.0 🟠
Simple but complete implementation of the JTA 1.1 API.

Narayana ★ 266 Apache-2.0 🟢
Provides support for traditional ACID and compensation transactions, also complies with JTA, JTS and other standards.

Seata ★ 26.0k Apache-2.0 🟢
Delivers high performance and easy to use distributed transaction services under a microservices architecture.

Tools that handle the distribution of applications in native formats.

Artipie ★ 691 MIT 🟢
Binary artifact management toolkit which hosts them on the file system or S3.

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

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.

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

Getdown ★ 528 🟠
System for deploying Java applications to end-user computers and keeping them up to date. Developed as an alternative to Java Web Start.

IzPack ★ 354 Apache-2.0 🟢
Setup authoring tool for cross-platform deployments.

JavaPackager ★ 1.2k GPL-3.0 🟠
Maven and Gradle plugin which provides an easy way to package Java applications in native Windows, macOS or GNU/Linux executables, and generate installers for them.

jDeploy ★ 415 Apache-2.0 🟢
Deploy desktop apps as native Mac, Windows or Linux bundles.

jlink.online ★ 51 Apache-2.0 🟢
Builds optimized runtimes over HTTP.

Nexus ★ 2.7k EPL-1.0 🟢
Binary management with proxy and caching capabilities.

Nuts ★ 160 🟢
Installs and runs Java applications from Maven repositories, reusing descriptors and provisioning required JDKs.

packr ★ 2.6k Apache-2.0 🔴
Packs JARs, assets and the JVM for native distribution on Windows, Linux and macOS.

really-executable-jars-maven-plugin ★ 137 Apache-2.0 🟠
Maven plugin for making self-executing JARs.

Libraries that assist with processing office document formats.

Apache Tika ★ 4.1k Apache-2.0 🟢
Detects and extracts text and metadata from a wide range of document formats.

commonmark-java ★ 2.7k BSD-2-Clause 🟢
Parses and renders CommonMark-compatible Markdown.

documents4j ★ 586 Apache-2.0 🟠
API for document format conversion using third-party converters such as MS Word.

docx4j ★ 2.4k 🟢
Create and manipulate Microsoft Open XML files.

html-to-markdown ★ 873 MIT 🟢
Converts HTML to CommonMark-compatible Markdown through a Java binding.

JQuick Excel ★ 129 🟢
Configures Excel import, export, validation, formulas and charts through a declarative XML DSL.

xberg ★ 9.3k MIT 🟢
Extracts text, tables and metadata from PDFs, Office documents, images and other formats through a Java binding.

Libraries and SDKs for evaluating and managing feature flags.

Featureflip Java SDK ★ 2 Apache-2.0 🟢
Java SDK for the Featureflip hosted platform, evaluating flags locally from a streamed rule set with an OpenFeature provider available.

FF4J ★ 1.5k Apache-2.0 🟢
Feature Flags for Java.

OpenFeature Java SDK ★ 128 Apache-2.0 🟢
Vendor-neutral API for evaluating feature flags in Java applications.

Rollgate Java SDK ★ 3 MIT 🟢
Java SDK for evaluating Rollgate feature flags with real-time configuration updates.

Togglz ★ 1.0k Apache-2.0 🟢
Implementation of the Feature Toggles pattern.

Unleash Java SDK ★ 138 Apache-2.0 🟢
Java client SDK for the Unleash feature management platform.

Libraries related to the financial domain.

Cassandre ★ 661 GPL-3.0 🔴
Trading bot framework.

iban-commons ★ 12 Apache-2.0 🟢
Zero-dependency IBAN and BIC toolkit with allocation-free validation plus parsing and formatting for 127 countries.

Joda-Money ★ 678 Apache-2.0 🟠
Basic currency and money classes and algorithms not provided by the JDK.

nablatensor ★ 3 Apache-2.0 🟢
Adjoint automatic differentiation for quantitative finance; records a valuation once and replays the tape to get a price and every Greek from one reverse sweep, on CPU, SIMD or GPU.

OpenGamma Strata ★ 963 Apache-2.0 🟢
Analytics and market risk library for financial products.

PesaFlow4J ★ 1 MIT 🟢
Dependency-free SDK for the Kenya PesaFlow/eCitizen PaymentAPI, including M-Pesa STK push and webhook signature verification.

Philadelphia ★ 346 Apache-2.0 🟢
Low-latency financial information exchange.

Stripe ★ 1.0k MIT 🟢
Integration with the Stripe API.

ta4j ★ 2.5k 🟢
Library for technical analysis.

Wickra ★ 56 Apache-2.0 🟢
Technical-analysis library with 514 streaming O(1)-per-tick indicators on a native Rust core, on Maven Central as org.wickra:wickra; more indicators and incremental updates than the pure-Java ta4j.

XChange ★ 4.1k MIT 🟢
Consistent Java API for market data and trading across cryptocurrency exchanges.

Frameworks and libraries for reading and writing fixed-length and delimited flat files.

BeanIO ★ 69 Apache-2.0 🔴
Maps flat files of fixed-length or delimited records to and from Java beans using XML or annotation configuration.

fixedformat4j ★ 53 Apache-2.0 🟢
Annotation-driven mapping of fixed-width flat files to and from POJOs and Java records.

Flatpack ★ 64 Apache-2.0 🟠
Parses and writes delimited and fixed-length flat files with optional column-mapping definitions.

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

Checker Framework ★ 1.2k 🟢
Pluggable type systems. Includes nullness types, physical units, immutability types and more. (GPL-2.0-only WITH Classpath-exception-2.0)

Daikon ★ 265 🟢
Detects likely program invariants and generates JML specs based on those invariants.

Java Path Finder (JPF) ★ 620 🟢
JVM formal verification tool containing a model checker and more. Created by NASA.

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 ★ 88 🟢
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 ★ 185 🟢
Translates JML specifications into SMT-LIB format and passes the proof problems implied by the program to backend solvers. (GPL-2.0-only)

Libraries that facilitate functional programming.

Fugue
Functional extensions to Guava.

Functional Java ★ 1.6k 🔴
Implements numerous basic and advanced programming abstractions that assist composition-oriented development.

jOOλ ★ 2.1k Apache-2.0 🔴
Extension to Java 8 that aims to fix gaps in lambda by providing numerous missing types and a rich set of sequential Stream API additions.

Packrat ★ 29 Apache-2.0 🟢
Gatherers library for Java Stream API. Gatherers can enhance streams with custom intermediate operations.

Parallel Collectors ★ 679 Apache-2.0 🟢
Stream API Collectors for parallel processing with custom thread pools, designed for I/O-heavy workloads.

protonpack ★ 488 MIT 🟠
Collection of stream utilities.

StreamEx ★ 2.3k Apache-2.0 🟢
Enhances Java 8 Streams.

Vavr ★ 6.2k Apache-2.0 🟢
Functional component library that provides persistent data types and functional control structures.

Frameworks that support the development of games.

FXGL ★ 4.9k MIT 🟢
JavaFX Game Development Framework.

input4j ★ 30 MIT 🟢
Lightweight, cross-platform library for gamepad and joystick input handling.

JBox2D ★ 1.1k BSD-2-Clause 🔴
Port of the renowned C++ 2D physics engine.

jMonkeyEngine ★ 4.3k BSD-3-Clause 🟢
Game engine for modern 3D development.

libGDX ★ 25.4k Apache-2.0 🟢
All-round cross-platform, high-level framework.

Litiengine ★ 836 MIT 🟢
AWT-based, lightweight 2D game engine.

LWJGL ★ 5.5k BSD-3-Clause 🟢
Robust framework that abstracts libraries like OpenGL/CL/AL.

Pathetic ★ 391 MIT 🟢
A highly configurable 3D A* pathfinding library that uses specific optimizations for high performance.

vulkan4j ★ 99 BSD-3-Clause 🔴
Vulkan, OpenGL ES2 and GLFW Memory Allocator bindings.

Libraries for working with geospatial data and algorithms.

Apache SIS ★ 126 Apache-2.0 🟢
Library for developing geospatial applications.

ArcGIS Maps SDK for Java ★ 131 Apache-2.0 🔴
JavaFX library for adding mapping and GIS functionality to desktop apps.

Geo ★ 435 Apache-2.0 🟢
GeoHash utilities in Java.

GeoTools ★ 1.9k LGPL-2.1 🟢
Library that provides tools for geospatial data.

GraphHopper ★ 6.7k Apache-2.0 🟢
Road-routing engine. Used as a Java library or standalone web service.

H2GIS ★ 224 LGPL-3.0 🟢
Spatial extension of the H2 database.

IP2Location.io Java SDK ★ 11 MIT 🟠
Wrapper for the IP2Location.io Geolocation API and the IP2WHOIS domain WHOIS API.

Jgeohash ★ 68 Apache-2.0 🔴
Library for using the GeoHash algorithm.

JTS ★ 2.2k 🟢
Geometry model and algorithms for manipulating vector geospatial data.

Mapsforge ★ 1.4k LGPL-3.0 🟢
Map rendering based on OpenStreetMap data.

Open Location Code ★ 4.4k Apache-2.0 🟠
Encodes geographic coordinates as short, shareable Plus Codes.

Spatial4j ★ 961 🟢
General-purpose spatial/geospatial library.

Libraries to create modern graphical user interfaces.

ControlsFX ★ 1.7k BSD-3-Clause 🟢
UI controls and components that complement JavaFX.

FlatLaf ★ 4.3k Apache-2.0 🟢
Modern Swing Look and Feel with Darcula and IntelliJ themes.

JavaFX ★ 3.3k GPL-2.0 🟢
Successor of Swing.

Scene Builder ★ 825 🟠
Visual layout tool for JavaFX applications.

Sierra ★ 153 Apache-2.0 🟢
Lightwieght declarative DSL for rapid development of Swing applications.

SnapKit ★ 329 🟢
Modern Java UI library for both desktop and web.

SWT ★ 199 EPL-2.0 🟢
Graphical widget toolkit.

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

Agrona ★ 3.3k Apache-2.0 🟢
Data structures and utility methods that are common in high-performance applications.

Disruptor ★ 18.5k Apache-2.0 🔴
Inter-thread messaging library.

Eclipse Collections ★ 2.6k 🟢
Collections framework inspired by Smalltalk.

fastutil ★ 2.2k Apache-2.0 🟢
Fast and compact type-specific collections.

Hollow ★ 1.4k Apache-2.0 🟢
High-performance in-memory datasets distributed from a single producer to many consumers.

HPPC ★ 1.1k Apache-2.0 🟢
Primitive collections.

JCTools ★ 3.9k Apache-2.0 🟢
Concurrency tools currently missing from the JDK.

TransmittableThreadLocal ★ 8.3k Apache-2.0 🟠
Propagates thread-local context across thread pools and asynchronous execution.

Libraries that assist with creating HTTP requests and/or binding responses.

Apache HttpComponents ★ 2.0k 🟢
Toolset of low-level Java components focused on HTTP and related protocols.

Async Http Client ★ 6.4k Apache-2.0 🟢
Asynchronous HTTP and WebSocket client library.

Feign ★ 9.8k Apache-2.0 🟢
HTTP client binder inspired by Retrofit, JAXRS-2.0, and WebSocket.

Google HTTP Client ★ 1.4k Apache-2.0 🟢
Pluggable HTTP transport abstraction with support for java.net.HttpURLConnection, Apache HTTP Client, Android, Google App Engine, XML, Gson, Jackson and Protobuf.

JQuickCurl ★ 1.1k Apache-2.0 🟢
Executes HTTP requests from cURL syntax through annotations, XML configuration and dynamic proxy clients.

methanol ★ 299 MIT 🟠
HTTP client extensions library.

OkHttp ★ 47.1k Apache-2.0 🟢
HTTP client for the JVM, Android and GraalVM.

Retrofit ★ 43.9k Apache-2.0 🟢
Typesafe REST client.

Ribbon ★ 4.6k Apache-2.0 🟠
Client-side IPC library that is battle-tested in the cloud.

Riptide ★ 341 MIT 🟢
Client-side response routing for Spring's RestTemplate.

unirest-java ★ 2.7k MIT 🟢
Simplified, lightweight HTTP client library.

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

Eclipse Java IDE ★ 648 EPL-2.0 🟢
Extensible Java IDE assembled from the Eclipse Platform, JDT and PDE.

Explyt ★ 25 🟢
AI coding agent for JetBrains IDEs that uses IDE indexes, refactorings, test runners, static analysis and debugging for Java and Kotlin projects.

IntelliJ IDEA ★ 20.6k 🟢
Supports many JVM languages and provides good options for Android development. The commercial edition targets the enterprise sector.

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

NetBeans ★ 3.1k Apache-2.0 🟢
Provides integration for several Java SE and EE features, from database access to HTML5.

SnapCode ★ 46 🟢
Modern IDE for Java running in the browser, focused on education.

Visual Studio Code Java ★ 3.8k 🟢
Extension suite providing Java language support, debugging, testing, Maven, Gradle and project management in Visual Studio Code.

Libraries that assist with the creation, evaluation or manipulation of graphical images.

Barcode-Lib4J ★ 19 Apache-2.0 🟢
Generates QR Code, DataMatrix, and other 1D/2D barcodes as vector (PDF, EPS, SVG) and raster (PNG, BMP, JPG) images with DPI awareness, high precision, and CMYK color model support.

Glide ★ 35.0k 🟢
Image loading and caching library for Android focused on smooth scrolling.

image-comparison ★ 400 Apache-2.0 🟢
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.

Imgscalr ★ 1.2k Apache-2.0 🔴
Simple, efficient and hardware-accelerated image-scaling library implemented in pure Java 2D.

scrimage ★ 1.2k Apache-2.0 🟢
Immutable, functional, and performant JVM library for manipulation of images.

Tess4J ★ 1.8k Apache-2.0 🟢
JNA wrapper for Tesseract OCR API.

Thumbnailator ★ 5.4k MIT 🟠
High-quality thumbnail generation library.

TwelveMonkeys ★ 2.1k BSD-3-Clause 🟢
Collection of plugins that extend the number of supported image file formats.

vips-ffm ★ 139 Apache-2.0 🟢
Comprehensive bindings for libvips, using Java's "Foreign Function & Memory" API.

webcam-capture ★ 2.4k MIT 🟠
Library for using built-in and external webcams directly in Java.

ZXing ★ 34.1k Apache-2.0 🟢
Multi-format 1D/2D barcode image processing library.

Libraries that help make the Java introspection and reflection API easier and faster to use.

ClassGraph ★ 3.0k MIT 🟢
ClassGraph (formerly FastClasspathScanner) is an uber-fast, ultra-lightweight, parallelized classpath scanner and module scanner for Java, Scala, Kotlin and other JVM languages.

jOOR ★ 2.8k Apache-2.0 🔴
jOOR stands for jOOR Object Oriented Reflection. It is a simple wrapper for the java.lang.reflect package.

Objenesis ★ 630 Apache-2.0 🟢
Allows dynamic instantiation without default constructor, e.g. constructors which have required arguments, side effects or throw exceptions.

ReflectASM ★ 1.5k BSD-3-Clause 🔴
ReflectASM is a very small Java library that provides high performance reflection by using code generation.

TypeTools ★ 628 Apache-2.0 🔴
Tools for resolving generic types.

Libraries for scheduling background jobs.

db-scheduler ★ 1.7k Apache-2.0 🟢
Persistent and cluster-friendly scheduler.

JobRunr ★ 3.1k 🟢
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.

Quartz ★ 6.8k Apache-2.0 🟢
Feature-rich, open source job scheduling library that can be integrated within virtually any Java application.

shedlock ★ 4.2k Apache-2.0 🟢
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.

Sundial ★ 281 Apache-2.0 🟠
Lightweight framework to simply define jobs, define triggers and start the scheduler.

Wisp ★ 149 Apache-2.0 🟠
Simple library with minimal footprint and straightforward API.

XXL-JOB ★ 30.6k GPL-3.0 🟢
Distributed task scheduling platform with centralized administration and execution monitoring.

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

Avaje Jsonb ★ 96 Apache-2.0 🟢
Reflection-free Json binding via source code generation with Jackson-like annotations.

DSL-JSON ★ 1.1k BSD-3-Clause 🟢
JSON library with advanced compile time databinding.

Fastjson2 ★ 4.4k Apache-2.0 🟢
High-performance JSON parser, serializer and object mapper.

Gson ★ 24.2k Apache-2.0 🟢
Serializes objects to JSON and vice versa. Good performance with on-the-fly usage.

Jackson ★ 9.8k 🟢
Similar to GSON, but offers performance gains if you need to instantiate the library more often.

jackson-modules-java8 ★ 425 Apache-2.0 🟢
Set of Jackson modules for Java 8 datatypes and features.

Jolt ★ 1.7k Apache-2.0 🟢
JSON to JSON transformation tool.

JSON-io ★ 388 Apache-2.0 🟢
Convert Java to JSON/TOON and back. Supports complex object graphs, cyclic references, and TOON format for 40-50% LLM token savings.

JsonPath ★ 9.5k Apache-2.0 🟠
Extract data from JSON using XPATH-like syntax.

JsonSurfer ★ 318 MIT 🔴
Streaming JsonPath processor dedicated to processing big and complicated JSON data.

Moshi ★ 10.2k Apache-2.0 🟢
Modern JSON library, less opinionated and uses built-in types like List and Map.

Yasson ★ 218 🟢
Binding layer between classes and JSON documents similar to JAXB.

Current implementations of the JVM/JDK.

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

Dragonwell8 ★ 4.3k GPL-2.0 🟢
Downstream version of OpenJDK optimized for online e-commerce, financial, logistics applications.

Eclipse Temurin ★ 1.2k Apache-2.0 🟢
OpenJDK distribution from the Eclipse Adoptium project.

Graal ★ 21.7k 🟢
Polyglot embeddable JVM. (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)

Microsoft JDK ★ 345 MIT 🟢
Microsoft Build of OpenJDK, Free, Open Source, Freshly Brewed!

Open JDK ★ 23.4k GPL-2.0 🟢
Open JDK community home.

OpenJ9 ★ 3.5k 🟢
High performance, enterprise-calibre, flexibly licensed, openly-governed cross-platform JVM extending and augmenting the runtime technology components from the Eclipse OMR and OpenJDK project.

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

SAP Machine ★ 622 GPL-2.0 🟢
SAP's no-cost, rigorously tested and JCK-verified OpenJDK friendly fork.

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

Libraries that log the behavior of an application.

Apache Log4j 2 ★ 3.6k Apache-2.0 🟢
Complete rewrite with a powerful plugin and configuration architecture.

Echopraxia ★ 60 🔴
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.

Flogger ★ 1.5k Apache-2.0 🟢
Flogger is a fluent logging API for Java. It supports a wide variety of features, and has many benefits over existing logging APIs.

Graylog ★ 8.1k 🟢
Open-source aggregator suited for extended role and permission management. (GPL-3.0-only)

Kibana ★ 21.3k 🟢
Analyzes and visualizes log files. Some features require payment.

Logback ★ 3.2k 🟢
Robust logging library with interesting configuration options via Groovy.

Logbook ★ 2.1k MIT 🟢
Extensible, open-source library for HTTP request and response logging.

Logstash ★ 14.9k 🟢
Tool for managing log files.

SLF4J ★ 2.5k MIT 🟢
Abstraction layer/simple logging facade.

tinylog ★ 775 Apache-2.0 🟢
Lightweight logging framework with static logger class.

Tools that provide specific statistical algorithms for learning from data.

Apache Mahout ★ 2.3k Apache-2.0 🟢
Scalable algorithms focused on collaborative filtering, clustering and classification.

DatumBox ★ 1.1k Apache-2.0 🔴
Provides several algorithms and pre-trained models for natural language processing.

Deeplearning4j ★ 14.3k Apache-2.0 🟢
Distributed and multi-threaded deep learning library.

DJL ★ 4.9k Apache-2.0 🟢
High-level and engine-agnostic framework for deep learning.

H2O ★ 7.5k Apache-2.0 🟢
Analytics engine for statistics over big data.

Intelligent java ★ 65 Apache-2.0 🔴
Seamlessly integrate with remote deep learning and language models programmatically.

JSAT ★ 795 GPL-3.0 🔴
Algorithms for pre-processing, classification, regression, and clustering with support for multi-threaded execution.

LIBSVM ★ 4.7k BSD-3-Clause 🟠
Support vector machine library with Java bindings and command-line tools.

Neureka ★ 91 MIT 🟠
A lightweight, platform independent, OpenCL accelerated nd-array/tensor library.

oj! Algorithms ★ 505 MIT 🟢
High-performance mathematics, linear algebra and optimisation needed for data science, machine learning and scientific computing.

sklearn-java ★ 4 Apache-2.0 🟢
Implements scikit-learn-style machine learning algorithms in pure Java.

Smile ★ 6.4k 🟢
Statistical Machine Intelligence and Learning Engine provides a set of machine learning algorithms and a visualization library.

Tribuo ★ 1.4k Apache-2.0 🟠
Provides tools for classification, regression, clustering, model development and interfaces with other libraries such as scikit-learn, pytorch and TensorFlow.

Weka
Collection of algorithms for data mining tasks ranging from pre-processing to visualization.

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

Aeron ★ 8.9k Apache-2.0 🟢
Efficient, reliable, unicast and multicast message transport.

Apache ActiveMQ ★ 2.5k Apache-2.0 🟢
Message broker that implements JMS and converts synchronous to asynchronous communication.

Apache Camel ★ 6.3k Apache-2.0 🟢
Glues together different transport APIs via Enterprise Integration Patterns.

Apache Kafka ★ 33.8k Apache-2.0 🟢
High-throughput distributed messaging system.

Apache Pulsar ★ 15.3k Apache-2.0 🟢
Distributed pub/sub-messaging system.

Apache Qpid for Java ★ 213 Apache-2.0 🟢
Java messaging clients and brokers implementing AMQP.

Apache RocketMQ ★ 22.6k Apache-2.0 🟢
Fast, reliable, and scalable distributed messaging platform.

AutoMQ ★ 10.8k Apache-2.0 🟢
AutoMQ is a cloud-native, serverless reinvented Kafka that is easily scalable, manage-less and cost-effective.

CloudEvents Java SDK ★ 446 Apache-2.0 🟢
Java SDK for creating, serializing and transporting CloudEvents.

Emissary ★ 109 Apache-2.0 🟢
Simple, lightweight, yet FAST messaging library for decoupling messages (requests and events) and message handlers.

Hermes ★ 870 🟢
Fast and reliable message broker built on top of Kafka.

HiveMQ MQTT Client ★ 1.1k Apache-2.0 🟢
Reactive and blocking Java client for MQTT 3.1.1 and MQTT 5.

JeroMQ ★ 2.5k MPL-2.0 🟠
Implementation of ZeroMQ.

NATS client ★ 679 Apache-2.0 🟢
NATS client.

Pushy ★ 1.9k MIT 🟢
Java library for sending Apple Push Notification service messages.

RabbitMQ Java client ★ 1.3k 🟢
RabbitMQ client.

Simple Java Mail ★ 1.3k Apache-2.0 🟢
Mailing with a clean and fluent API.

Smack ★ 2.4k Apache-2.0 🟢
Cross-platform XMPP client library.

Svix ★ 3.4k MIT 🟢
Library for the Svix API to send webhooks and verify signatures.

Tools for creating and managing microservices.

Armeria ★ 5.1k Apache-2.0 🟢
Asynchronous RPC/REST client/server library built on top of Java 8, Netty, HTTP/2, Thrift and gRPC.

Eureka ★ 12.7k Apache-2.0 🟢
REST-based service registry for resilient load balancing and failover.

gRPC Spring ★ 3.7k Apache-2.0 🟢
Spring Boot integration for building gRPC clients and servers.

Helidon ★ 3.8k Apache-2.0 🟢
Two-style approach for writing microservices: Functional-reactive and as an implementation of MicroProfile.

Micronaut ★ 6.4k Apache-2.0 🟢
Modern full-stack framework with focus on modularity, minimal memory footprint and startup time.

Nacos ★ 33.4k Apache-2.0 🟢
Dynamic service discovery, configuration and service management platform for building cloud native applications.

Quarkus ★ 15.9k Apache-2.0 🟢
Kubernetes stack tailored for the HotSpot and Graal VM.

Sentinel ★ 23.1k Apache-2.0 🟠
Flow control component enabling reliability, resilience and monitoring for microservices.

Everything else.

JBake ★ 1.2k MIT 🟠
Static website generator.

JObfuscator
Source code obfuscator.

yGuard ★ 479 MIT 🟠
Obfuscation via renaming and shrinking.

Tools for creating or managing mobile applications.

Codename One ★ 1.9k 🟢
Cross-platform Java framework for native mobile, desktop, web and watch apps. (GPL-2.0-only WITH Classpath-exception-2.0)

Gluon Substrate ★ 447 GPL-2.0 🟠
Builds native JavaFX applications for desktop, mobile and embedded targets.

MobileUI ★ 14 MIT 🔴
Cross-platform framework for developing mobile apps with native UI in Java and Kotlin.

Multi-OS Engine ★ 598 Apache-2.0 🟢
Open-source, cross-platform engine to develop native mobile (iOS, Android, etc.) apps.

Tools that observe/monitor applications in production by providing telemetry.

Apitally ★ 7 MIT 🟢
Simple, privacy-focused API monitoring, analytics and request logging for Spring Boot apps.

Arthas ★ 37.6k Apache-2.0 🟢
Allows to troubleshoot production issues for applications without modifying code or restarting servers.

Automon ★ 571 Apache-2.0 🔴
Combines the power of AOP with monitoring and/or logging tools.

Boot Usage Spring Boot Starter ★ 3 Apache-2.0 🟢
Spring Boot Actuator extension providing application startup and runtime metrics including JVM uptime, memory usage, and CPU load.

BTrace ★ 6.0k Apache-2.0 🟢
Dynamic tracing and diagnostics for running JVM applications without restarts.

Datadog ★ 737 Apache-2.0 🟢
Modern monitoring & analytics.

Dropwizard Metrics ★ 7.8k Apache-2.0 🟢
Expose metrics via JMX or HTTP and send them to a database.

Glowroot ★ 1.4k Apache-2.0 🟢
Open-source Java APM.

HertzBeat ★ 7.4k Apache-2.0 🟢
Real-time monitoring system with custom-monitor and agentless.

hippo4j ★ 6.0k Apache-2.0 🟠
Dynamic and observable thread pool framework.

inspectIT Ocelot ★ 222 Apache-2.0 🟠
Java agent that collects application performance, tracing and behavioral data.

JavaMelody ★ 3.0k Apache-2.0 🟢
Performance monitoring and profiling.

Jolokia ★ 850 Apache-2.0 🟢
JMX over REST.

Micrometer ★ 4.9k Apache-2.0 🟢
Vendor-neutral metrics/observability facade for the most popular metrics/observability libraries.

Micrometer Tracing ★ 299 Apache-2.0 🟢
Vendor-neutral distributed tracing facade for the most popular tracer libraries.

OpenTelemetry ★ 2.5k Apache-2.0 🟢
Instrument, generate, collect, and export telemetry data to help you analyze your software’s performance and behavior.

Pinpoint ★ 13.9k Apache-2.0 🟢
Open-source APM tool.

Prometheus ★ 2.3k Apache-2.0 🟢
Provides a multi-dimensional data model, DSL, autonomous server nodes and much more.

Sentry ★ 1.4k MIT 🟢
Integration with Sentry, an application error tracking and performance analysis platform.

SPM ★ 25 Apache-2.0 🟢
Performance monitor with distributing transaction tracing for JVM apps.

StatLite ★ 138 MIT 🟢
Self-hosted monitoring dashboard with direct Spring Boot Actuator/Micrometer and Quarkus integrations, SQLite storage, and no Prometheus or Grafana required.

zipkin ★ 17.5k Apache-2.0 🟢
Distributed tracing system which gathers timing data needed to troubleshoot latency problems in microservice architectures.

For working with platform-specific native libraries.

Aparapi
Converts bytecode to OpenCL which allows execution on GPUs.

JavaCPP ★ 4.7k 🟢
Provides efficient and easy access to native C++.

JCuda ★ 268 MIT 🔴
JCuda offers Java bindings for CUDA and CUDA-related libraries.

JNA ★ 8.9k 🟢
Work with native libraries without writing JNI. Also provides interfaces to common system libraries.

JNR ★ 1.3k 🟢
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.

native-lib-loader ★ 221 🔴
Native library loader for extracting and loading native libraries from Java.

Libraries that specialize in processing text.

Apache OpenNLP ★ 1.6k Apache-2.0 🟢
Toolkit for machine-learning-based natural language processing.

CoreNLP ★ 10.1k GPL-3.0 🟢
Provides a set of fundamental tools for tasks like tagging, named entity recognition, and sentiment analysis.

DKPro ★ 204 🟢
Collection of reusable NLP tools for linguistic pre-processing, machine learning, lexical resources, etc.

Hypherator ★ 5 MIT 🔴
Java hyphenation library with iterator-like interface. Can be used out-of-the box - dictionaries for multiple languages are bundled in.

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

Libraries for building network clients and servers.

AISmessages ★ 171 🟢
Decodes NMEA-armoured AIS messages for maritime navigation and safety systems with ITU-R M.1371 support and no runtime dependencies. (CC-BY-NC-SA-4.0)

Apache MINA sshd ★ 1.1k Apache-2.0 🟢
Java implementation of SSH clients, servers, SFTP and SCP.

Atmosphere ★ 3.8k Apache-2.0 🟢
Real-time transport framework supporting WebSocket, SSE, gRPC and WebTransport.

Commons-networking ★ 22 Apache-2.0 🔴
Client for server-sent events (SSE).

dnsjava ★ 1.1k BSD-3-Clause 🟢
Java implementation of the DNS protocol.

Drift ★ 250 Apache-2.0 🟢
Easy-to-use, annotation-based library for creating Thrift clients and serializable types.

Dubbo ★ 41.6k Apache-2.0 🟢
High-performance RPC framework.

Fluency ★ 167 Apache-2.0 🟢
High throughput data ingestion logger to Fluentd and Fluent Bit.

Grizzly ★ 180 🟢
NIO framework. Used as a network layer in Glassfish.

gRPC-java ★ 12.1k Apache-2.0 🟢
RPC framework based on protobuf and HTTP/2.

java-ngrok ★ 60 MIT 🟢
Java wrapper for ngrok; programmatic tunnels for ingress, webhooks, demos, and APIs.

Java-WebSocket ★ 10.8k MIT 🟠
Lightweight WebSocket client and server implementation.

MINA ★ 922 Apache-2.0 🟢
Abstract, event-driven async I/O API for network operations over TCP/IP and UDP/IP via Java NIO.

MinimalFTP ★ 193 Apache-2.0 🔴
Lightweight, small and customizable FTP server.

Netty ★ 35.1k Apache-2.0 🟢
Framework for building high-performance network applications.

ServiceTalk ★ 1.0k Apache-2.0 🟢
Framework built on Netty with APIs tailored to specific protocols and support for multiple programming paradigms.

Socket.IO Client Java ★ 5.4k 🔴
Java client for Socket.IO servers.

sshj ★ 2.7k Apache-2.0 🟢
Programmatically use SSH, SCP or SFTP.

TLS Channel ★ 209 MIT 🟠
Implements a ByteChannel interface over SSLEngine, enabling easy-to-use (socket-like) TLS.

Undertow ★ 3.8k Apache-2.0 🟢
Web server providing both blocking and non-blocking APIs based on NIO. Used as a network layer in WildFly.

urnlib ★ 36 GPL-3.0 🟠
Represent, parse and encode URNs, as in RFC 2141.

WebSocket4Java ★ 4 MIT 🟢
WebSocket framework based on JDK NIO and virtual threads, with zero third-party dependencies at runtime.

APIs that handle the persistence of objects.

Apache Cayenne ★ 345 🟢
Provides a clean, static API for data access. Also includes a GUI Modeler for working with database mappings, and DB reverse engineering and generation.

Doma ★ 508 Apache-2.0 🟢
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 ★ 1.5k Apache-2.0 🟢
Provides simple and fast data access.

EclipseLink ★ 246 🟢
Supports a number of persistence standards: JPA, JAXB, JCA and SDO.

Ekbatan ★ 21 Apache-2.0 🟢
Modern Java persistence framework for event-driven systems, with an ergonomic outbox that commits state and events in one transaction.

Hibernate ★ 6.5k Apache-2.0 🟢
Robust and widely used, with an active community.

MyBatis ★ 20.4k Apache-2.0 🟢
Couples objects with stored procedures or SQL statements.

mybatis-dynamic ★ 5 🟠
Code-first dynamic ORM for MyBatis with runtime schema modification.

MyBatis-Plus ★ 17.5k Apache-2.0 🟢
A powerful enhanced toolkit of MyBatis for simplifying development.

ObjectiveSql ★ 1.3k Apache-2.0 🔴
ActiveRecord ORM for rapid development and convention over configuration.

Permazen ★ 425 Apache-2.0 🟠
Language-natural persistence layer.

SimpleFlatMapper ★ 460 MIT 🔴
Simple database and CSV mapper.

Ujorm ★ 12 Apache-2.0 🟢
Maps rows to JavaBeans or Java records with no third-party runtime dependencies, deliberately omitting lazy loading, 1:M collections and transaction management.

Java platform as a service.

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

AWS Lambda
Serverless computation.

Google Cloud
Google's cloud infrastructure.

Heroku
Abstract computing environments.

Microsoft Azure
Microsoft's cloud infrastructure.

OpenShift
Provides additionally an on-premise solution.

Tools to help with PDF files.

Apache FOP ★ 229 Apache-2.0 🟢
Creates PDFs from XSL-FO.

Apache PDFBox ★ 3.1k Apache-2.0 🟢
Toolbox for creating and manipulating PDFs.

DynamicReports ★ 246 LGPL-3.0 🟠
Simplifies JasperReports.

Eclipse BIRT ★ 546 EPL-2.0 🟢
Report engine for creating PDF and other formats (DOCX, XLSX, HTML, etc) using Eclipse-based visual editor.

flyingsaucer ★ 2.2k 🟢
XML/XHTML and CSS 2.1 renderer. (LGPL-2.1-or-later)

GraphCompose ★ 113 MIT 🟢
Declarative engine for structured business PDFs with semantic layout, atomic pagination, theme tokens, and native vector charts.

iText ★ 2.3k 🟢
Creates PDF files programmatically.

JasperReports ★ 1.4k LGPL-3.0 🟢
Complex reporting engine.

jquick-pdf ★ 226 🟢
Generates PDFs from HTML-like templates and ECharts-style charts using iText 7, without a browser dependency.

Nostrum Dynamic Jasper ★ 1 LGPL-3.0 🟠
Provides dynamic report layouts on top of JasperReports.

Open HTML to PDF ★ 286 🟢
Properly supports modern PDF standards based on flyingsaucer and Apache PDFBox.

OpenDataLoader PDF ★ 29.3k Apache-2.0 🟢
Parses PDFs into structured Markdown, JSON and HTML through a Java API and command line.

OpenPDF ★ 4.4k 🟢
Open-source iText fork. (LGPL-3.0-only & MPL-2.0)

Tools for performance analysis, profiling and benchmarking.

Argus ★ 17 MIT 🟢
JVM diagnostics CLI for jcmd, JFR, async-profiler, heap analysis and machine-readable health verdicts.

async-profiler ★ 9.2k Apache-2.0 🟢
Low-overhead sampling profiler for CPU, allocation and lock analysis on the JVM.

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.

Heap Seance ★ 4 Apache-2.0 🟠
Memory leak diagnostics that orchestrates jcmd, jmap, jstat, JFR, Eclipse MAT, and async-profiler into a structured investigation workflow with confidence-based verdicts.

JDK Mission Control ★ 986 🟢
Profiling and diagnostics suite for JVM applications using Java Flight Recorder.

jHiccup ★ 705 🟠
Logs and records platform JVM stalls.

JITWatch ★ 3.3k 🟢
Analyze the JIT compiler optimisations made by the HotSpot JVM.

JMH ★ 2.7k GPL-2.0 🟢
Harness for building, running, and analysing nano/micro/milli/macro benchmarks written in Java and other languages targeting the JVM.

JVM Hotpath ★ 11 MIT 🟠
Java agent for line-level execution frequency analysis to identify algorithmic bottlenecks.

LatencyUtils ★ 464 🔴
Utilities for latency measurement and reporting.

ThreadMine
Web-based analyzer for JVM thread dumps from HotSpot, OpenJ9, Zing and GraalVM that detects deadlocks, pool exhaustion and virtual thread pinning. Free tier with paid plans.

ThreadMine Anonymizer ★ 1 MIT 🟢
Local CLI that replaces an application's own package, class, method and thread names in JVM thread dumps with keyed tokens, keeps JDK and framework frames intact so the dump stays analyzable, and unmasks the analyzer's report afterwards.

Frameworks that are suites of multiple libraries encompassing several categories.

BCEL ★ 274 Apache-2.0 🟢
Byte Code Engineering Library - analyze, create, and manipulate Java class files.

BeanUtils ★ 324 Apache-2.0 🟢
Easy-to-use wrappers around the Java reflection and introspection APIs.

BSF ★ 32 Apache-2.0 🟢
Bean Scripting Framework - interface to scripting languages, including JSR-223.

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

CLI ★ 392 Apache-2.0 🟢
Command-line arguments parser.

CLI2
Redesign of Commons CLI.

Codec ★ 490 Apache-2.0 🟢
General encoding/decoding algorithms, e.g. phonetic, base64 or URL.

Collections ★ 726 Apache-2.0 🟢
Extends or augments the Java Collections Framework.

Compress ★ 406 Apache-2.0 🟢
Defines an API for working with tar, zip and bzip2 files.

Configuration ★ 214 Apache-2.0 🟢
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 ★ 416 Apache-2.0 🟢
Component for reading and writing comma separated value files.

Daemon ★ 106 Apache-2.0 🟢
Alternative invocation mechanism for unix-daemon-like java code.

DBCP ★ 369 Apache-2.0 🟢
Database connection pooling services.

DbUtils ★ 392 Apache-2.0 🟢
JDBC helper library.

Digester ★ 62 Apache-2.0 🟢
XML-to-Java-object mapping utility.

Email ★ 178 Apache-2.0 🟢
Library for sending e-mail from Java.

Exec ★ 163 Apache-2.0 🟢
API for dealing with external process execution and environment management in Java.

FileUpload ★ 262 Apache-2.0 🟢
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.

Graph ★ 45 Apache-2.0 🟢
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 ★ 486 Apache-2.0 🟢
Image library.

IO ★ 1.1k Apache-2.0 🟢
Collection of I/O utilities.

Javaflow
Continuation implementation to capture the state of the application.

JCI ★ 22 Apache-2.0 🟢
Java Compiler Interface.

JCS ★ 108 Apache-2.0 🟢
Java Caching System.

Jelly ★ 26 Apache-2.0 🟢
XML based scripting and processing engine.

Jexl ★ 241 Apache-2.0 🟢
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 ★ 43 Apache-2.0 🟢
Utilities for manipulating Java Beans using the XPath syntax.

Lang ★ 3.0k Apache-2.0 🟢
Provides extra functionality for classes in java.lang.

Logging ★ 171 Apache-2.0 🟢
Wrapper around a variety of logging API implementations.

Math ★ 657 Apache-2.0 🟢
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 ★ 297 Apache-2.0 🟢
Collection of network utilities and protocol implementations.

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 ★ 554 Apache-2.0 🟢
Generic object pooling component.

RDF ★ 59 Apache-2.0 🟢
Common implementation of RDF 1.1 that could be implemented by systems on the JVM.

RNG ★ 66 Apache-2.0 🟢
Commons Rng provides implementations of pseudo-random numbers generators.

SCXML ★ 68 Apache-2.0 🟢
Implementation of the State Chart XML specification aimed at creating and maintaining a Java SCXML engine.

Validator ★ 232 Apache-2.0 🟢
Framework to define validators and validation rules in an xml file.

VFS ★ 251 Apache-2.0 🟢
Virtual File System component for treating files, FTP, SMB, ZIP and such like as a single logical file system.

Weaver ★ 29 Apache-2.0 🟢
Provides an easy way to enhance (weave) compiled bytecode.

CUBA Platform ★ 704 Apache-2.0 🟢
High-level framework for developing enterprise applications with a rich web interface, based on Spring, EclipseLink and Vaadin.

Light-4J ★ 3.7k Apache-2.0 🟢
Fast, lightweight and productive microservices framework with built-in security.

Spring Framework ★ 60.3k Apache-2.0 🟢
Comprehensive application framework for building Java applications.

Libraries that help the management of operating system processes.

ch.vorburger.exec ★ 42 Apache-2.0 🟢
Convenient API around Apache Commons Exec.

zt-exec ★ 917 Apache-2.0 🟢
Provides a unified API to Apache Commons Exec and ProcessBuilder.

zt-process-killer ★ 140 Apache-2.0 🟢
Stops processes started from Java or the system processes via PID.

Java proxy and gateway servers for routing and mediating traffic.

LittleProxy ★ 150 Apache-2.0 🟢
High performance HTTP proxy atop Netty's event-based networking library.

Membrane Service Proxy ★ 642 Apache-2.0 🟢
Open-source, reverse-proxy framework.

OpenIG ★ 93 🟢
High-performance reverse proxy server with specialized session management and credential replay functionality.

Spring Cloud Gateway ★ 4.9k Apache-2.0 🟢
API gateway built on Spring Framework and Spring Boot.

Zuul ★ 14.1k Apache-2.0 🟢
Gateway service that provides dynamic routing, monitoring, resiliency, security, and more.

Libraries for developing reactive applications.

Akka ★ 13.3k 🟢
Toolkit and runtime for building concurrent, distributed, fault-tolerant and event-driven applications.

Reactive Streams ★ 4.9k MIT-0 🔴
Provides a standard for asynchronous stream processing with non-blocking backpressure.

Reactor ★ 3.7k Apache-2.0 🟢
A framework for building non-blocking applications on the JVM, providing support for reactive programming.

RxJava ★ 48.2k Apache-2.0 🟢
Allows for composing asynchronous and event-based programs using observable sequences.

vert.x ★ 14.7k 🟢
Polyglot event-driven application framework.

Libraries and engines for building and evaluating regular expressions.

dregex ★ 56 BSD-2-Clause 🟠
Regular expression engine that uses deterministic finite automata. It supports some Perl-style features and yet retains linear matching time, and also offers set operations.

JavaVerbalExpressions ★ 2.6k MIT 🟢
Library that helps with constructing difficult regular expressions.

RE2/J ★ 1.3k 🟠
Java port of RE2 providing linear-time regular expression matching.

Sift ★ 92 Apache-2.0 🟢
Type-safe, AST-based Regex Builder focused on readability and ReDoS prevention.

Frameworks specifically for creating RESTful services.

Dropwizard ★ 8.6k Apache-2.0 🟢
Opinionated framework for setting up modern web applications with Jetty, Jackson, Jersey and Metrics.

Elide ★ 1.0k 🟢
Opinionated framework for JSON- or GraphQL-APIs based on a JPA data model.

hate ★ 26 MIT 🔴
Builds hypermedia-friendly objects according to HAL specification.

Jersey ★ 730 🟢
JAX-RS reference implementation.

OfficeFloor ★ 71 Apache-2.0 🟢
Spring Boot add-on that adds explicit function orchestration to REST endpoints, with each endpoint's steps, branches and error flows in one YAML file whose directory path maps to the URL.

openapi-generator ★ 26.8k Apache-2.0 🟢
Allows generation of API client libraries, SDKs, server stubs, documentation and configuration automatically given an OpenAPI Spec.

RESTEasy ★ 1.1k Apache-2.0 🟢
Fully certified and portable implementation of the JAX-RS specification.

RestExpress ★ 938 Apache-2.0 🟠
Thin wrapper on the JBoss Netty HTTP stack that provides scaling and performance.

Restlet Framework ★ 667 🟢
Pioneering framework with powerful routing and filtering capabilities, and a unified client and server API.

Spark ★ 15 Apache-2.0 🔴
Sinatra inspired framework.

Spring HATEOAS ★ 1.1k Apache-2.0 🟢
Standalone and Spring support for building hypermedia-based APIs using HAL, HAL FORMS, Collection+JSON, ALPS and UBER.

springdoc-openapi ★ 3.7k Apache-2.0 🟢
Automates the generation of API documentation using Spring Boot projects.

Swagger Java ★ 8.6k Apache-2.0 🟢
Java libraries for generating, parsing and serving OpenAPI definitions.

Libraries for scientific computing, analysis and visualization.

BioJava ★ 632 LGPL-2.1 🟢
Facilitates processing biological data by providing algorithms, file format parsers, sequencing and 3D visualization commonly used in bioinformatics.

Chart-FX ★ 613 LGPL-3.0 🟠
Scientific charting library with focus on performance optimised real-time data visualisation at 25 Hz update rates for large data sets.

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

Erdos ★ 129 MIT 🔴
Modular, light and easy graph framework for theoretic algorithms.

Gephi ★ 6.7k GPL-3.0 🟢
Cross-platform for visualizing and manipulating large graph networks.

JFreeChart ★ 1.4k LGPL-2.1 🟠
2D chart library for Swing, JavaFX and server-side applications.

JGraphT ★ 2.8k EPL-2.0 🟢
Graph library that provides mathematical graph-theory objects and algorithms.

jSciPy ★ 23 MIT 🟠
jSciPy is a Java library designed for scientific computing, offering functionalities inspired by popular scientific computing libraries. It currently provides modules for signal processing, including Butterworth filters, peak finding algorithms, and an RK4 solver for ordinary differential equations.

LogicNG ★ 157 Apache-2.0 🟢
Library for creating, manipulating and solving Boolean and Pseudo-Boolean formulas.

Mines Java Toolkit ★ 87 Apache-2.0 🔴
Library for geophysical scientific computation, visualization and digital signal analysis.

Orekit ★ 295 Apache-2.0 🟢
A low level space flight dynamics library providing basic elements (orbits, dates, attitude, frames...) and various algorithms (conversions, propagations, pointing...) to handle them.

Orson-Charts ★ 123 GPL-3.0 🔴
Generates a wide variety of 3D charts that can be displayed with Swing and JavaFX or exported to PDF, SVG, PNG and JPEG.

XChart ★ 1.6k Apache-2.0 🟢
Light-weight library for plotting data. Many customizable chart types are available.

Tools and runtimes for using Java or Java-like languages as scripts.

JBang ★ 1.9k MIT 🟢
JBang makes it easy to use Java for scripting. It lets you use a single file for code and dependency management and allows you to run it directly.

JPad
Snippet runner.

JQuick Java ★ 412 🟢
Java-like scripting language for dynamic rule engines with XML orchestration and Java interoperability.

Engines that index documents for search and analysis.

Apache Lucene ★ 3.6k Apache-2.0 🟢
High-performance, full-featured, cross-platform, text search engine library.

Apache Solr ★ 1.7k Apache-2.0 🟢
Enterprise search engine optimized for high-volume traffic.

Elasticsearch ★ 77.9k 🟢
Distributed, multitenant-capable, full-text search engine with a RESTful web interface and schema-free JSON documents.

Elasticsearch Java Client ★ 524 Apache-2.0 🟢
Official typed Java client for Elasticsearch.

OpenSearch ★ 13.7k Apache-2.0 🟢
Distributed search and analytics engine derived from Elasticsearch.

Viglet Turing ES ★ 22 Apache-2.0 🟢
Self-hosted enterprise search platform with faceted, semantic and hybrid search, RAG, AI agents and pluggable Solr, Elasticsearch or Lucene backends.

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

Apache Shiro ★ 4.5k Apache-2.0 🟢
Performs authentication, authorization, cryptography and session management.

Ayza ★ 579 Apache-2.0 🟢
High-level SSL configuration builder for configuring HTTP clients and servers with SSL/TLS.

Bashkit4j ★ 3 MIT 🟢
Sandboxed bash interpreter for running untrusted scripts in-process: in-memory filesystem, opt-in allowlisted host mounts, network denied by default.

Bouncy Castle ★ 2.7k MIT 🟢
All-purpose cryptographic library and JCA provider offering a wide range of functions, from basic helpers to PGP/SMIME operations.

Certificate Ripper ★ 926 Apache-2.0 🟢
CLI tool and library for extracting and exporting server certificates from HTTPS endpoints.

Cryptomator ★ 16.2k GPL-3.0 🟢
Multiplatform, transparent, client-side encryption of files in the cloud.

Dependency-Track ★ 4.2k Apache-2.0 🟢
Software composition analysis platform for identifying supply-chain risk.

Jasypt Spring Boot ★ 3.1k MIT 🟠
Integrates encrypted properties with Spring Boot applications.

jjwt ★ 11.1k Apache-2.0 🟢
JSON web token for Java and Android.

Jwks RSA ★ 207 MIT 🟢
JSON Web Key Set parser.

jwt-java ★ 15 MIT 🔴
Easily create and parse JSON Web Tokens and create customized JWT validators using a fluent API.

Keycloak ★ 36.9k Apache-2.0 🟢
Integrated SSO and IDM for browser apps and RESTful web services.

MOSS ★ 0 🟢
Cryptographic signing for AI agents using ML-DSA-44 post-quantum signatures, creating audit trails for attribution and compliance.

Nbvcxz ★ 311 MIT 🟢
Advanced password strength estimation.

OpenAM ★ 895 🟢
Access management solution that includes authentication, SSO, authorization, federation, entitlements and web services security.

OTP-Java ★ 242 MIT 🟢
One-time password generator library according to RFC 4226 (HOTP) and RFC 6238 (TOTP).

OWASP Dependency-Check ★ 7.7k Apache-2.0 🟢
Detects publicly disclosed vulnerabilities contained within a project's dependencies.

pac4j ★ 2.5k Apache-2.0 🟢
Security engine.

Passay ★ 318 🟠
Enforce password policy by validating candidate passwords against a configurable rule set.

Password4j ★ 432 Apache-2.0 🟠
User-friendly cryptographic library that supports Argon2, Bcrypt, Scrypt, PBKDF2 and various other cryptographic hash functions.

ScribeJava ★ 5.5k MIT 🟠
OAuth client library supporting OAuth 1.0a, OAuth 2.0 and numerous providers.

SecurityBuilder ★ 49 Apache-2.0 🔴
Fluent Builder API for JCA and JSSE classes and especially X.509 certificates.

Spring Security ★ 9.6k Apache-2.0 🟢
Authentication and access-control framework with OAuth 2.1 and OpenID Connect authorization server support.

Themis ★ 2.0k Apache-2.0 🟠
Multi-platform high-level cryptographic library provides easy-to-use encryption for protecting sensitive data: secure messaging with forward secrecy, secure data storage (AES256GCM); suits for building end-to-end encrypted applications.

Tink ★ 305 Apache-2.0 🟢
Provides a simple and misuse-proof API for common cryptographic tasks.

Topaz ★ 1.4k Apache-2.0 🟢
Fine-grained authorization for applications with support for RBAC, ABAC, and ReBAC.

WebAuthn4J ★ 593 Apache-2.0 🟢
Server-side WebAuthn and passkey verification library.

Libraries that handle serialization with high efficiency.

Apache Avro ★ 3.3k Apache-2.0 🟢
Data interchange format with dynamic typing, untagged data, and absence of manually assigned IDs.

Apache Fory ★ 4.6k Apache-2.0 🟢
High-performance object graph serialization framework with JIT and zero-copy support.

Apache Orc ★ 769 Apache-2.0 🟢
Fast and efficient columnar storage format for Hadoop-based workloads.

Apache Parquet ★ 3.1k Apache-2.0 🟢
Columnar storage format based on assembly algorithms from Google's paper on Dremel.

Apache Thrift ★ 11.0k Apache-2.0 🟢
Data interchange format that originated at Facebook.

FlatBuffers ★ 26.5k Apache-2.0 🟢
Memory-efficient serialization library that can access serialized data without unpacking and parsing it.

Kryo ★ 6.5k BSD-3-Clause 🟢
Fast and efficient object graph serialization framework.

MessagePack ★ 1.5k Apache-2.0 🟢
Efficient binary serialization format.

Protobuf ★ 72.1k 🟢
Google's data interchange format.

SBE ★ 3.5k Apache-2.0 🟢
Simple Binary Encoding, one of the fastest message formats around.

Wire ★ 4.4k Apache-2.0 🟢
Clean, lightweight protocol buffers.

XMLBeam ★ 77 Apache-2.0 🔴
Processes XML by using annotations or XPath within code.

Servers specifically used to deploy applications.

Apache Tomcat ★ 8.3k Apache-2.0 🟢
Robust, all-round server for Servlet and JSP.

Apache TomEE ★ 479 Apache-2.0 🟢
Tomcat plus Java EE.

Jetty ★ 4.1k 🟢
Provides a Web server and javax.servlet container, plus support for HTTP/2, WebSocket, OSGi, JMX, JNDI, JAAS and many other integrations.

WildFly ★ 3.2k Apache-2.0 🟢
Formerly known as JBoss and developed by Red Hat with extensive Java EE support.

Libraries for reading, writing and generating spreadsheet files.

Apache Fesod ★ 6.2k Apache-2.0 🟢
Memory-efficient library for reading and writing large spreadsheet files.

Apache POI ★ 2.3k 🟢
Supports OOXML (XLSX, DOCX, PPTX) as well as OLE2 (XLS, DOC or PPT).

fastexcel ★ 914 🟢
High performance library to read and write large Excel (XLSX) worksheets.

jackson-dataformat-spreadsheet ★ 23 Apache-2.0 🟢
Jackson dataformat module for reading and writing Excel (XLSX/XLS) as POJOs via ObjectMapper.

Jxls ★ 531 Apache-2.0 🟢
Generates Excel reports from spreadsheet templates.

Sheetz ★ 100 Apache-2.0 🟢
Reads and writes Excel, CSV and ODS files with annotation mapping, streaming, styling and validation.

zerocell ★ 83 Apache-2.0 🔴
Annotation-based API for reading data from Excel sheets into POJOs with focus on reduced overhead.

Tools that substitute expressions in a template.

Freemarker ★ 1.1k Apache-2.0 🟢
Library to generate text output (HTML web pages, e-mails, configuration files, source code, etc.) based on templates and changing data.

Handlebars.java ★ 1.6k 🟢
Logicless and semantic Mustache templates.

Jamal ★ 69 Apache-2.0 🔴
Extendable template engine embedded into Maven/JavaDoc, supporting multiple extensions (Groovy, Ruby, JavaScript, JShell, PlantUml) with support for snippet handling.

jstachio ★ 332 BSD-3-Clause 🔴
Typesafe Mustache templating engine.

jte ★ 1.1k Apache-2.0 🟢
Compiles to classes, and uses an easy syntax, several features to make development easier and provides fast execution and a small footprint.

Pebble ★ 1.2k BSD-3-Clause 🟢
Inspired by Twig and separates itself with its inheritance feature and its easy-to-read syntax. It ships with built-in autoescaping for security and it includes integrated support for internationalization.

Rocker ★ 782 🟠
Optimized, memory efficient and speedy template engine producing statically typed, plain objects.

StringTemplate ★ 1.0k 🔴
Template engine for generating source code, web pages, emails, or any other formatted text output.

Thymeleaf ★ 3.0k Apache-2.0 🟠
Aims to be a substitute for JSP and works for XML files.

Tools that test from model to the view.

Testing for the software development process that emerged from TDD and was heavily influenced by DDD and OOAD.

Cucumber ★ 2.8k MIT 🟢
Provides a way to describe features in a plain language which customers can understand.

J8Spec ★ 49 MIT 🔴
Follows a Jasmine-like syntax.

JBehave ★ 40 BSD-3-Clause 🟠
Extensively configurable framework that describes stories.

JGiven ★ 464 Apache-2.0 🟢
Provides a fluent API which allows for simpler composition.

Kensa ★ 23 Apache-2.0 🟢
Code-first BDD framework for Java and Kotlin that generates interactive HTML reports and sequence diagrams from test code.

Serenity BDD ★ 755 🟢
Automated Acceptance testing and reporting library that works with Cucumber, JBehave and JUnit to make it easier to write high quality executable specifications.

Everything related to the creation and handling of random data.

AutoParams ★ 368 MIT 🟠
Supports generating test data or combining scenarios for parameterized tests.

Datafaker ★ 1.8k Apache-2.0 🟢
Modern fake data generator forked from Java Faker.

Instancio ★ 1.2k Apache-2.0 🟢
Automates data setup in unit tests by generating fully-populated, reproducible objects. Includes JUnit 5 extension.

jFairy ★ 744 Apache-2.0 🟢
Fake data generator.

JMock ★ 206 Apache-2.0 🟢
JMock is a high-performance data generation and simulation component library implemented in Java.

Randomized Testing ★ 184 Apache-2.0 🟢
JUnit test runner and plugins for running JUnit tests with pseudo-randomness.

Provide environments to run tests for a specific use case.

BitDive Java Agent ★ 84 🟠
Java agent that captures runtime traces, SQL queries and HTTP payloads for BitDive testing.

jqwik ★ 849 EPL-2.0 🟢
Engine for property-based testing built on JUnit 5.

JUnit ★ 7.1k EPL-2.0 🟢
Common testing framework.

PIT ★ 1.9k Apache-2.0 🟢
Fast mutation-testing framework for evaluating fault-detection abilities of existing JUnit or TestNG test suites.

Robolectric ★ 6.0k 🟢
Runs Android tests on the JVM without an emulator or device.

selenium ★ 34.5k Apache-2.0 🟢
Browser automation framework and ecosystem.

Selenium Boot ★ 12 🟢
Zero-boilerplate Selenium + TestNG framework with auto driver management, smart retry, self-healing locators, AI failure analysis, and a built-in HTML report.

Tools for integration, service and contract testing.

Arquillian ★ 388 Apache-2.0 🟢
Integration and functional testing platform for Java EE containers.

cdi-test ★ 31 Apache-2.0 🟢
JUnit extension for easy and efficient testing of CDI components.

Citrus ★ 485 Apache-2.0 🟢
Integration testing framework that focuses on both client- and server-side messaging.

GreenMail ★ 744 Apache-2.0 🟢
In-memory email server for integration testing. Supports SMTP, POP3 and IMAP including SSL.

Hoverfly Java ★ 177 Apache-2.0 🟠
Native bindings for Hoverfly, a proxy which allows you to simulate HTTP services.

Karate ★ 9.0k MIT 🟢
DSL that combines API test-automation, mocks and performance-testing making testing REST/HTTP services easy.

kubetest4j ★ 23 Apache-2.0 🟢
Declarative, annotation-based testing library for Kubernetes and OpenShift with automatic resource lifecycle management, multi-cluster support, and integrated log collection.

Pact JVM ★ 1.1k Apache-2.0 🟢
Consumer-driven contract testing.

REST Assured ★ 7.1k Apache-2.0 🟢
DSL for easy testing of REST/HTTP services.

Testcontainers ★ 8.7k MIT 🟢
Provides throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

WebTau ★ 384 Apache-2.0 🟠
Test across REST-API, Graph QL, Browser, Database, CLI and Business Logic with consistent set of matchers and concepts.

weld-testing ★ 116 Apache-2.0 🟢
Set of test framework extensions (JUnit 4, JUnit 5, Spock) to enhance the testing of CDI components via Weld. Supports Weld 5.

Libraries that provide custom matchers.

AssertJ ★ 2.8k Apache-2.0 🟢
Fluent assertions that improve readability.

JsonUnit ★ 1.0k Apache-2.0 🟢
Library that simplifies JSON comparison in tests.

Truth ★ 2.8k Apache-2.0 🟢
Google's fluent assertion and proposition framework.

XMLUnit ★ 320 Apache-2.0 🟢
Simplifies testing for XML output.

Other stuff related to testing.

Awaitility ★ 4.0k Apache-2.0 🟠
DSL for synchronizing asynchronous operations.

ConcurrentUnit ★ 419 Apache-2.0 🔴
Toolkit for testing multi-threaded and asynchronous applications.

ConsoleCaptor ★ 35 Apache-2.0 🟢
Captures console output for unit testing purposes.

junit-dataprovider ★ 250 Apache-2.0 🟠
TestNG-like data provider/runner for JUnit.

junit-pioneer ★ 618 EPL-2.0 🟢
JUnit 5 extension pack, pushing the frontiers on Jupiter.

log-capture ★ 16 MIT 🟠
Captures log entries and provides assertions for unit and integration testing.

LogCaptor ★ 432 Apache-2.0 🟢
Captures log entries for unit testing purposes.

Qualflare TestNG ★ 0 Apache-2.0 🟢
TestNG listener that keeps every retry attempt and reports timeouts and configuration failures as distinct statuses.

Selfie ★ 101 Apache-2.0 🟢
Snapshot testing (inline and on disk).

skipper-java ★ 5 MIT 🟠
Real-time test execution control via Google Spreadsheet, enabling instant toggle without code changes.

Stebz ★ 21 MIT 🟢
Multi-approach framework for test steps managing.

test-watch-maven-plugin ★ 2 MIT 🟠
Maven plugin providing Vitest-inspired watch mode for tests with smart selection and parallel execution.

Tools which mock collaborators to help testing single, isolated units.

EasyMock ★ 832 🟢
EasyMock is a Java library that provides an easy way to use Mock Objects in unit testing.

JMockit ★ 473 🔴
Integration testing, API mocking and faking, and code coverage.

Mockito ★ 15.5k MIT 🟢
Mocking framework that lets you write tests with a clean and simple API.

MockServer ★ 5.0k Apache-2.0 🟢
Allows mocking of systems integrated with HTTPS.

Moco ★ 4.4k MIT 🟠
Concise web services for stubs and mocks.

WireMock ★ 7.4k Apache-2.0 🟢
Stubs and mocks web services.

Tools for load and performance testing.

Apache JMeter ★ 9.5k Apache-2.0 🟢
Functional testing and performance measurements.

Gatling ★ 7.0k Apache-2.0 🟢
Load testing tool designed for ease of use, maintainability and high performance.

JMeter DSL.java ★ 538 Apache-2.0 🟢
Load tests with JMeter as simple as a JUnit test.

Libraries which provide general utility functions.

bucket4j ★ 2.8k Apache-2.0 🟢
Rate limiting library based on token-bucket algorithm.

cactoos ★ 782 MIT 🟢
Collection of object-oriented primitives.

fswatch ★ 34 Apache-2.0 🟢
Micro library to watch for directory file system changes, simplifying java.nio.file.WatchService.

Guava ★ 51.9k Apache-2.0 🟢
Collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and more.

ISBN core ★ 7 MIT 🟢
A small library that contains a representation object of ISBN-10 and ISBN-13 and tools to parse, validate and format one.

Java Diff Utils ★ 1.5k Apache-2.0 🟢
Utilities for text or data comparison and patching.

Java UUID Generator ★ 943 Apache-2.0 🟢
Generates standard UUID versions including time-ordered UUIDv6 and UUIDv7.

java-refined ★ 7 MIT 🟠
Zero-dependency refinement types for Java 8+ with type-safe wrappers covering numerics, strings, and collections.

java-util ★ 442 Apache-2.0 🟢
Zero-dependency, high-performance utilities featuring Converter (universal type conversion), DeepEquals, CaseInsensitiveMap, TTLCache, CompactMap, MultiKeyMap, and object graph traversal.

JEmoji ★ 117 Apache-2.0 🟢
An auto-generated emoji library that provides type-safe direct access to emojis and alias support for Discord, Slack, GitHub and many more features.

Jimfs ★ 2.6k Apache-2.0 🟢
In-memory file system.

JKScope ★ 24 Apache-2.0 🔴
Java scope functions inspired by Kotlin.

PipelinR ★ 493 MIT 🟠
Small utility library for using handlers and commands with pipelines.

Semver4j ★ 118 MIT 🟢
Lightweight library that helps you handling semantic versioning with different modes.

spring-chain-of-responsibility ★ 3 Apache-2.0 🟢
Autowires Spring Boot beans into a Chain of Responsibility via @Order and @ChainNext, no manual wiring.

Underscore-java ★ 551 MIT 🟢
Port of Underscore.js functions.

Zip4j ★ 2.2k Apache-2.0 🟠
Reads, writes, encrypts and streams ZIP files.

Utilities that help create the development shell environment and switch between different Java versions.

jabba ★ 330 Apache-2.0 🟠
Java Version Manager inspired by nvm. Supports macOS, Linux and Windows.

jenv ★ 6.7k MIT 🟠
Java Version Manager inspired by rbenv. Can configure globally or per project. Tested on Debian and macOS.

SDKMan ★ 6.9k Apache-2.0 🟢
Java Version Manager inspired by RVM and rbenv. Supports UNIX-based platforms and Windows.

Libraries that analyze the content of websites.

Apache Nutch ★ 3.3k Apache-2.0 🟢
Highly extensible, highly scalable web crawler for production environments.

crawlberg ★ 177 MIT 🟢
Crawls and scrapes websites through a Java binding with Markdown conversion and optional browser rendering.

jsoup ★ 11.4k MIT 🟢
Scrapes, parses, manipulates and cleans HTML.

Norconex Crawler ★ 204 Apache-2.0 🟢
Modular web and file-system crawler with embedded Java APIs, official Docker images and a browser-based configurator.

StormCrawler ★ 996 Apache-2.0 🟢
SDK for building low-latency and scalable web crawlers.

webmagic ★ 11.7k Apache-2.0 🟠
Scalable crawler with downloading, url management, content extraction and persistent.

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

ActiveJ ★ 997 Apache-2.0 🟠
Lightweight asynchronous framework built from the ground up for developing high-performance web applications.

Apache Tapestry ★ 137 Apache-2.0 🟢
Component-oriented framework for creating dynamic, robust, highly scalable web applications.

Apache Wicket ★ 796 Apache-2.0 🟢
Component-based web application framework similar to Tapestry, with a stateful GUI.

Blade ★ 5.9k Apache-2.0 🟠
Lightweight, modular framework that aims to be elegant and simple.

Bootique ★ 1.4k Apache-2.0 🟢
Minimally opinionated framework for runnable apps.

Erupt ★ 2.8k Apache-2.0 🟢
Annotation-Driven Low-Code & JPA Visualization.

Javalin ★ 8.3k Apache-2.0 🟢
Microframework for web applications.

Jooby ★ 1.8k Apache-2.0 🟢
Scalable, fast and modular micro-framework that offers multiple programming models.

Ninja ★ 1.9k Apache-2.0 🟠
Full-stack web framework.

Pippo ★ 787 Apache-2.0 🟠
Small, highly modularized, Sinatra-like framework.

Play ★ 12.6k Apache-2.0 🟢
Built on Akka, it provides predictable and minimal resource consumption (CPU, memory, threads) for highly-scalable applications in Java and Scala.

PrimeFaces ★ 1.9k MIT 🟢
JSF framework with both free and commercial/support versions and frontend components.

Ratpack ★ 1.9k 🟢
Set of libraries that facilitate fast, efficient, evolvable and well-tested HTTP applications.

Spring Boot ★ 81.5k Apache-2.0 🟢
Framework for creating stand-alone, production-grade Spring applications.

Takes ★ 878 MIT 🟢
Opinionated web framework which is built around the concepts of True Object-Oriented Programming and immutability.

tinystruct ★ 354 Apache-2.0 🟢
Lightweight, pluggable framework for building Java applications with CLI, HTTP, and modular extension support.

Vaadin ★ 1.7k 🟢
Full-stack Java platform for building browser applications with server-side components.

webforJ ★ 72 MIT 🟢
Full-stack platform that composes the UI in Java on the server using a library of web components.

WebForms Core
A technology for managing HTML tags from the server.

Engines for orchestrating long-running workflows and business processes.

Activiti ★ 10.5k Apache-2.0 🟢
Embeddable BPMN workflow and business process engine.

Apache DolphinScheduler ★ 14.5k Apache-2.0 🟢
Distributed workflow orchestration platform with visual and API-driven scheduling.

Cadence Java Client ★ 154 Apache-2.0 🟢
Java client and workflow framework for the Cadence orchestration service.

Conductor ★ 32.2k Apache-2.0 🟢
Event-driven workflow engine for distributed applications and AI agents.

flowable ★ 9.5k Apache-2.0 🟢
Compact and efficient workflow and business process management platform.

Maestro ★ 3.8k Apache-2.0 🟢
Workflow orchestration engine developed by Netflix.

Temporal Java SDK ★ 433 Apache-2.0 🟢
Java SDK for writing durable workflows and activities on Temporal.

Awesome Lists related to the Java & JVM ecosystem.

Awesome Annotation Processing

Awesome Graal

Awesome Gradle Plugins

Awesome Hybris

Awesome J2ME

Awesome Java libraries and hidden gems

Awesome JVM

Awesome Microservices

Awesome REST

Awesome Selenium

AwesomeJavaFX

ciandcd

Useful Java Links

Active discussions.

foojay.io

r/java
Subreddit for the Java community.

Stack Overflow
Question/answer platform.

Guides, tutorials, examples and practical references for Java developers.

Design Patterns
Implementation and explanation of the most common design patterns.

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

Google Java Style

Java Algorithms and Clients

Java Concurrency Checklist

Java Developer Roadmap

Java Evolved
Side-by-side comparisons of legacy and modern Java patterns.

Modern Java - A Guide to Java 8
Popular Java 8 guide.

TheCodeForge Java Tutorials

Which JDK
Overview of common JVMs with pros and cons.

Books that made a big impact and are still worth reading.

Core Java Volume I--Fundamentals

Core Java, Volume II--Advanced Features

Effective Java (3rd Edition)

Head First Java (3rd Edition)

Java Concurrency in Practice

The Well-Grounded Java Developer (2nd Edition)

Thinking in Java

Something to look at or listen to while programming.

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

A Bootiful Podcast

Foojay Podcast

Inside Java
Official podcast.

Java Off Heap

Active accounts to follow. Descriptions from their socials.

Adam Bien
Freelance author, JavaOne Rockstar speaker, consultant, Java Champion.

Aleksey Shipilëv
Performance geek, benchmarking czar, 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.

Chris Engelbert
Open Source Enthusiast, Speaker, Developer, Developer Advocacy at TimescaleDB.

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

Ed Burns
Consulting Member of the Technical Staff at Oracle.

Eugen Paraschiv
Author of the Spring Security Course.

Heinz Kabutz
Java Champion, speaker, author of The Java Specialists' Newsletter, concurrency performance expert.

Holly Cummins
Technical Lead of IBM London's Bluemix Garage, Java Champion, developer, author, JavaOne rockstar.

James Weaver
Java/JavaFX/IoT developer, author and speaker.

Java
Official Java Twitter account.

Javin Paul
Well-known Java blogger.

Josh Long
Spring Advocate at Pivotal, author of O'Reilly's Cloud Native Java- and Building Microservices with Spring Boot, JavaOne Rock Star.

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

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.

Mario Fusco
RedHatter, JUG coordinator, frequent speaker and author.

Mark Heckler
Pivotal Principal Technologist and Developer Advocate, conference speaker, published author, and Java Champion, focusing on Internet of Things and the cloud.

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.

Monica Beckwith
Performance consultant, JavaOne Rock Star.

OpenJDK
Official OpenJDK account.

Peter Lawrey
Peter Lawrey, Java performance expert.

Randy Shoup
Stitch Fix VP Engineering, speaker, JavaOne Rock Star.

Reza Rahman
Java EE/GlassFish/WebLogic evangelist, author, speaker, open source hacker.

Sander Mak
Java Champion, author.

Simon Maple
Java Champion, VirtualJUG founder, LJC leader, RebelLabs author.

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

Stephen Colebourne
Java Champion, speaker.

Trisha Gee
Java Champion and speaker.

Venkat Subramaniam
Author, University of Houston professor, MicroSoft MVP award recipient, JavaOne Rock Star, Java Champion.

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

Sites to read.

Baeldung

Dzone

InfoQ

Java, SQL, and jOOQ

java.libhunt.com

Java.net

Javalobby

JavaWorld

JAXenter

RebelLabs

TheServerSide.com

Vanilla Java