Awesome Java

A curated list of noteworthy Java frameworks, libraries, tools and resources.

_{811 projects · 80 categories · 85 resources}

_{Activity: 🟢 pushed within 3 months · 🟠 pushed 3–12 months ago · 🔴 no push for over 12 months}

_{License chips use GitHub SPDX metadata when available.}

_{Entries spanning several repositories combine their stars, use the most recent push for activity and show a license only when all repositories agree.}

Projects

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 ★ 1.5k Apache-2.0 🟠
Annotations and interfaces to express design and architecture concepts in code.

jQAssistant ★ 285 GPL-3.0 🟢
Static code analysis with Neo4J-based query language.

Taikai ★ 244 MIT 🟢
ArchUnit extension with predefined architecture rules for common Java technologies.

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

A2A Java SDK ★ 467 Apache-2.0 🟢
Official Java SDK for the Agent2Agent protocol.

AgentScope Java ★ 4.8k 🟢
Framework for building distributed, long-running AI agents with tool execution, persistence and multi-agent orchestration.

Anahata ASI ★ 23 Apache-2.0 🟢
Java agent container with local LLM adapters, stateful tool execution, context management and IDE integration.

Dokimos ★ 48 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 ★ 385 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 ★ 19 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 ★ 12.8k Apache-2.0 🟢
Simplifies integration of LLMs with unified APIs and a comprehensive toolbox.

liter-llm ★ 240 MIT 🟢
Provides a Java binding for a unified LLM API client across multiple providers.

MCP Java SDK ★ 3.6k 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 ★ 1.4k 🟠
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 ★ 380 MIT 🟠
Library to use the OpenAI API (and compatible ones) in the simplest possible way.

Spring AI ★ 9.2k Apache-2.0 🟢
Application framework for AI engineering for Spring.

Spring AI Alibaba ★ 10.5k 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 ★ 8 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 ★ 5.3k 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 ★ 25.7k 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 ★ 850 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 ★ 18.7k 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 ★ 57 Apache-2.0 🟠
Generate Javadoc from your maven/gradle project and deploy it automatically on GitHub Page.

Jib ★ 14.4k Apache-2.0 🟢
Builds optimized container images for Java applications without a Docker daemon.

Maven Wrapper ★ 252 Apache-2.0 🟢
Analogue of Gradle Wrapper for Maven, allowing projects to build without a preinstalled Maven.

Polyglot for Maven ★ 922 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 ★ 15.6k GPL-3.0 🟢
Java 8 Jar & Android APK reverse engineering suite.

Byteman ★ 514 🟢
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 ★ 72 Apache-2.0 🟢
Provides low level bytecode generation.

Recaf ★ 7.3k MIT 🟢
JVM reverse engineering toolkit, essentially an IDE for Java bytecode.

Libraries that provide caching facilities.

cache2k ★ 742 Apache-2.0 🔴
In-memory high performance caching library.

Caffeine ★ 17.8k Apache-2.0 🟢
High-performance, near-optimal caching library.

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

Infinispan ★ 1.3k 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.

Argument Parsing 5 projects

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.

Text-Based User Interfaces 4 projects

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 ★ 936 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 ★ 9.0k 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 ★ 37 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 ★ 391 Apache-2.0 🟢
Detect uses of legacy Java APIs.

Mutability Detector ★ 246 Apache-2.0 🟠
Reports whether instances of a given class are immutable.

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

OpenRewrite ★ 3.6k Apache-2.0 🟢
Automates large-scale source-code refactoring through reusable recipes.

OpenTaint ★ 126 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.

RefactorFirst ★ 542 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 ★ 1.9k 🟢
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 ★ 40 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.

Tools that format or restructure Java source code.

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

JHarmonizer ★ 26 🟢
Safely reorders Java source code with configurable rules and Palantir Java Format.

Palantir Java Format ★ 856 Apache-2.0 🟢
Formatter based on google-java-format with wider lines and lambda-friendly output.

Spotless ★ 5.6k 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 ★ 48 Apache-2.0 🔴
Generates postman collection, environment and integration tests from java code.

CRUDGen ★ 11 Apache-2.0 🟢
Compile-time annotation processor generating CRUD layers, DTOs, JSON Patch, and custom HTTP endpoints for Spring Boot.

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

Geci ★ 138 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 ★ 22.4k Apache-2.0 🟢
Yeoman source code generator for Spring Boot and AngularJS.

Joda-Beans ★ 150 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 ★ 925 Apache-2.0 🟢
Companion builder class, withers and templates for Java records.

Spring CRUD Generator ★ 38 Apache-2.0 🟢
Maven plugin for generating Spring Boot CRUD applications from YAML/JSON specifications.

Telosys ★ 212 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 ★ 630 🔴
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 ★ 775 🟢
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 ★ 108 Apache-2.0 🟢
Loads yaml and properties files, supports dynamic configuration, plugins, file-watching and config event listeners.

centraldogma ★ 665 Apache-2.0 🟢
Highly-available version-controlled service configuration repository based on Git, ZooKeeper and HTTP/2.

ClearConfig ★ 9 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 ★ 466 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 ★ 47 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 ★ 102 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 ★ 63 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 ★ 283 LGPL-3.0 🟢
Configuration library supporting TOML, YAML, HOCON, JSON and in-memory formats.

owner ★ 939 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 ★ 771 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 ★ 1.7k 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 ★ 690 MIT 🟢
Performance-optimized, dependency-free and RFC 4180 compliant.

jackson-dataformat-csv ★ 454 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 ★ 26.2k 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 ★ 11.9k BSD-3-Clause 🟢
Tool for working with messy data: cleaning, transforming, extending it with web services and linking it to databases.

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

Smooks ★ 417 🟠
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 ★ 17 Apache-2.0 🟢
Provides indexed, SQL-like queries over Java collections.

HashSmith ★ 106 MIT 🟠
Hash map and set implementations using SwissTable-style SWAR/SIMD control-byte probing, optimized for memory efficiency.

Persistent Collection ★ 787 🔴
Persistent and immutable analogue of the Java Collections Framework.

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

Wormhole4j ★ 8 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 ★ 10.0k Apache-2.0 🟢
Distributed wide-column database with linear scalability and fault tolerance.

Apache Doris ★ 15.7k 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 ★ 209 Apache-2.0 🟢
ArangoDB Java driver.

ArcadeDB ★ 1.1k 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 ★ 640 Apache-2.0 🟢
Universal, flexible, high-performance distributed ID generator.

Debezium ★ 13.0k Apache-2.0 🟢
Low latency data streaming platform for change data capture.

druid ★ 14.0k Apache-2.0 🟢
High-performance, column-oriented, distributed data store.

eXist ★ 466 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 ★ 10.0k 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 ★ 12.3k 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.

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 ★ 16 Apache-2.0 🟠
Launcher for MariaDB that requires no installation or external dependencies.

Modality ★ 16 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 ★ 219 Apache-2.0 🟢
Type 3 JDBC driver and Layer 7 proxy server for decoupling applications from relational database connection management.

OpenDJ ★ 435 🟢
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 ★ 21 Apache-2.0 🔴
Build JPA Criteria queries using a Stream-like API.

QuestDB ★ 17.2k 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 ★ 40 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 ★ 104 Apache-2.0 🟠
Allows you to use MongoDB query language to query your relational database.

StarRocks ★ 12.0k Apache-2.0 🟢
Distributed SQL query engine for real-time analytics and data lakehouses.

Trino ★ 13.1k 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 ★ 836 BSD-3-Clause 🟢
Parse and build iCalendar RFC 5545 data models.

Jollyday ★ 134 Apache-2.0 🟢
Determines the holidays for a given year, country/name and eventually state/region.

ThreeTen-Extra ★ 423 BSD-3-Clause 🟢
Additional date-time classes that complement those in JDK 8.

Time4J ★ 471 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 ★ 4.1k 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 ★ 2.6k MIT 🟢
Java decompiler focused on modern language features.

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

jadx ★ 49.9k 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 ★ 2.3k 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 ★ 314 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 ★ 19 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 ★ 95 🟠
Lightweight and dynamic dependency injection framework.

Augmentation of the development process at a fundamental level.

AspectJ ★ 392 🟠
Seamless aspect-oriented programming extension.

Faux Pas ★ 143 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 ★ 71.8k 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 ★ 6.1k 🟢
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 ★ 414 🟢
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 ★ 130 Apache-2.0 🔴
Allows checked exceptions in functional interfaces and converts exceptions to Optional return.

RR4J ★ 25 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 ★ 30 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.

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 ★ 10.7k Apache-2.0 🟢
Functional fault tolerance library.

ScaleCube Services ★ 639 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 ★ 484 🟢
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 ★ 265 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 ★ 688 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 ★ 529 🟢
System for deploying Java applications to end-user computers and keeping them up to date. Developed as an alternative to Java Web Start.

IzPack ★ 353 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 ★ 2.6k EPL-1.0 🟢
Binary management with proxy and caching capabilities.

Nuts ★ 157 🟢
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 ★ 136 Apache-2.0 🟠
Maven plugin for making self-executing JARs.

Libraries that assist with processing office document formats.

Apache Tika ★ 3.9k 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 ★ 585 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 ★ 822 MIT 🟢
Converts HTML to CommonMark-compatible Markdown through a Java binding.

JQuick Excel ★ 130 🟢
Configures Excel import, export, validation, formulas and charts through a declarative XML DSL.

xberg ★ 8.8k 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.

FF4J ★ 1.4k Apache-2.0 🟢
Feature Flags for Java.

OpenFeature Java SDK ★ 127 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 ★ 137 Apache-2.0 🟢
Java client SDK for the Unleash feature management platform.

Libraries related to the financial domain.

Cassandre ★ 660 GPL-3.0 🔴
Trading bot framework.

Joda-Money ★ 679 Apache-2.0 🟠
Basic currency and money classes and algorithms not provided by the JDK.

OpenGamma Strata ★ 952 Apache-2.0 🟢
Analytics and market risk library for financial products.

Philadelphia ★ 344 Apache-2.0 🟢
Low-latency financial information exchange.

Stripe ★ 995 MIT 🟢
Integration with the Stripe API.

ta4j ★ 2.5k 🟢
Library for technical analysis.

Wickra ★ 36 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 ★ 68 Apache-2.0 🔴
Maps flat files of fixed-length or delimited records to and from Java beans using XML or annotation configuration.

fixedformat4j ★ 52 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 ★ 1.1k 🟢
Pluggable type systems. Includes nullness types, physical units, immutability types and more. (GPL-2.0-only WITH Classpath-exception-2.0)

Daikon ★ 255 🟢
Detects likely program invariants and generates JML specs based on those invariants.

Java Path Finder (JPF) ★ 615 🟢
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 ★ 182 🟢
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.