Topics / #java

Java projects on GitHub

Widely used object-oriented language running on the JVM, common in enterprise backends.

As of , the most-starred Java projects on GitHub are project-based-learning (287K stars), CS-Notes (186.3K stars) and JavaGuide (159.1K stars). GitHub.Locker tracks 450 Java repositories with 9.6M stars combined. The fastest-growing on October 16 was ghidra, with +757 stars in a day.

450Projects
9.6MStars in total
+3.4KStars in a day

Hot right now

Most stars gained in a day · Oct 16

The all-time top

Top 100 of 450 · by stars

  1. #1 · practical-tutorials/project-based-learning

    project-based-learning

    A curated list of programming tutorials where you learn by building a real application from scratch.

    287K
  2. #2 · CyC2018/CS-Notes

    CS-Notes

    CS-Notes is a huge Chinese-language collection of study notes covering the core topics of technical coding interviews: algorithms, LeetCode solutions, operating systems, computer networks, databases, Java, and system design.

    186.3K
  3. #3 · Snailclimb/JavaGuide

    JavaGuide

    JavaGuide is a free, open-source guide to Java and backend interviews: a collection of study notes and Q&A summaries covering Java core, computer science fundamentals, databases, and system design.

    159.1K
  1. 4

    hello-algo

    130.8Kkrahets/hello-algo · Java

    Hello Algo is a free, open-source illustrated book that teaches data structures and algorithms from scratch using animated diagrams and one-click runnable code.

  2. 5

    java-design-patterns

    94.8Kiluwatar/java-design-patterns · Java

    A collection of Java implementations for classic software design patterns (Creational, Structural, Behavioral and more), each shown as a well-commented, runnable code example.

  3. 6

    Stirling-PDF

    94.4KStirling-Tools/Stirling-PDF · TypeScript

    Stirling PDF is an open-source PDF editing platform with over 50 tools for editing, merging, splitting, signing, redacting, converting, OCR-ing, and compressing PDFs.

  4. 7

    opencv

    91.2Kopencv/opencv · C++

    OpenCV is a widely used open-source library for computer vision, image processing, and machine learning, offering tools for tasks like object detection, video analysis, and camera calibration.

  5. 8

    ghidra

    89.8KNationalSecurityAgency/ghidra · Java

    Ghidra is a software reverse engineering (SRE) framework created and maintained by the NSA's Research Directorate, used to disassemble, decompile, graph, and analyze compiled code.

  6. 9

    awesome-interview-questions

    85KDopplerHQ/awesome-interview-questions

    A curated list of lists of technical interview questions, covering dozens of languages, frameworks, databases, and topics like algorithms and system design.

  7. 10

    mall

    84.9Kmacrozheng/mall · Java

    Mall is a full e-commerce system with a storefront (mall-portal) and an admin backend (mall-admin), built on Spring Boot and MyBatis, meant as a complete reference implementation of online shopping.

  8. 11

    spring-boot

    81.7Kspring-projects/spring-boot · Java

    Spring Boot is a Java framework that helps you create production-grade, Spring-powered applications and services with minimal configuration fuss.

  9. 12

    advanced-java

    79.2Kdoocs/advanced-java · Java

    A free, community-curated collection of in-depth Java backend interview questions and answers, covering message queues, search engines, caching, sharding, distributed systems, high availability, microservices, and big-data processing.

  10. 13

    elasticsearch

    78.3Kelastic/elasticsearch · Java

    Elasticsearch is a distributed search and analytics engine, scalable data store, and vector database built for near real-time full-text search, vector search, and generative AI (RAG) use cases on production-scale data; it's the core of Elastic's Stack platform.

  11. 14

    LeetCodeAnimation

    76.7KMisterBooo/LeetCodeAnimation · Java

    LeetCodeAnimation is a collection of animated LeetCode problem walkthroughs: each animation shows how pointers move, how state and recursion unfold, and why boundaries hold, paired with reference code.

  12. 15

    awesome-machine-learning

    74.6Kjosephmisiti/awesome-machine-learning · Python

    A curated, community-maintained list of machine learning frameworks, libraries, and software, organized by programming language.

  13. 16

    protobuf

    72.1Kprotocolbuffers/protobuf · C++

    Protocol Buffers (protobuf) is Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data, similar to XML but smaller, faster, and simpler.

  14. 17

    daytona

    71.5Kdaytonaio/daytona

    Daytona is a secure, elastic infrastructure runtime for running AI-generated code inside isolated sandboxes, used by agents and developers through SDKs, an API, and a CLI.

  15. 18

    Java

    66.4KTheAlgorithms/Java · Java

    A GitHub collection of classic algorithms and data structures, each implemented in Java for educational purposes as part of The Algorithms project.

  16. 19

    interviews

    65.3Kkdn251/interviews · Java

    A curated study guide for coding interviews, covering data structures, algorithms, greedy algorithms, bitmasks, runtime analysis, plus links to video lectures, interview books, online judges and mock interview platforms.

  17. 20

    termux-app

    62.8Ktermux/termux-app · Java

    Termux is a terminal emulator app for Android that gives you a Linux-like environment on your phone, extendable with installable packages.

  18. 21

    leetcode-master

    62.7Kyoungyangyang04/leetcode-master · Shell

    This is a curated LeetCode study guide ('代码随想录') that organizes 200 classic problems into a step-by-step learning path, with detailed illustrated explanations, video breakdowns, and mind maps for mastering data structures and algorithms.

  19. 22

    architect-awesome

    60.8Kxingshaocheng/architect-awesome

    A curated technical roadmap in Chinese for backend engineers aiming to become architects, mapping out data structures, algorithms, concurrency, databases, middleware, and system design.

  20. 23

    spring-framework

    60.3Kspring-projects/spring-framework · Java

    Spring Framework is the foundational library for the entire Spring ecosystem, providing core infrastructure (dependency injection, AOP, data access, MVC, etc.) for building enterprise Java applications.

  21. 24

    awesome-android-ui

    58Kwasabeef/awesome-android-ui

    A curated list (awesome-list) of Android UI/UX libraries, organized by component type: layouts, buttons, lists/grids, view pagers, labels/forms, images, seek bars, progress indicators, menus, dialogs, calendars, graphs, animations, parallax, blur/other effects, and Jetpack Compose components.

  22. 25

    leetcode

    55.7Kazl397985856/leetcode · JavaScript

    A large, continuously growing collection of worked LeetCode solutions, algorithm and data-structure explainers, Anki flashcard decks, and a 'daily problem' archive, written by the author as he solved problems himself.

  23. 26

    dbeaver

    52.1Kdbeaver/dbeaver · Java

    DBeaver is a free universal database tool and SQL client for developers, DBAs and analysts, supporting almost any database that has a JDBC or ODBC driver.

  24. 27

    guava

    51.9Kgoogle/guava · Java

    Guava is a set of core Java libraries from Google, providing new collection types (multimap, multiset), immutable collections, a graph library, and utilities for concurrency, I/O, hashing, primitives, and strings. It is heavily used inside Google and by many other companies.

  25. 28

    jadx

    51Kskylot/jadx · Java

    jadx is a Dex to Java decompiler: command line and GUI tools that produce Java source code from Android Dex and Apk files.

  26. 29

    awesome-java

    49.3Kakullpp/awesome-java

    A curated list of frameworks, libraries, tools and resources for the Java programming language, organized into categories like AI, build tools, caching, CLI, bytecode manipulation and more.

  27. 30

    JeecgBoot

    48.2Kjeecgboot/JeecgBoot · Java

    JeecgBoot is an enterprise AI low-code platform: you describe what you need in natural language and it generates the front-end, back-end CRUD code, database tables and menu permissions, while also bundling a Dify-like AI app module with chat, RAG knowledge bases, flow orchestration and MCP plugins.

  28. 31

    GitHubDaily

    48.2KGitHubDaily/GitHubDaily

    GitHubDaily is a curated Chinese-language collection of interesting and useful open-source projects, developer tools, tutorials and tech news discovered on GitHub, shared daily since October 2015.

  29. 32

    RxJava

    48.2KReactiveX/RxJava · Java

    RxJava is a Java library (Reactive Extensions for the JVM) for composing asynchronous and event-based programs using observable sequences.

  30. 33

    okhttp

    47.1Klysine-dev/okhttp · Kotlin

    OkHttp is an efficient HTTP client for the JVM, Android, and GraalVM, handling HTTP/1.1, HTTP/2, websockets, and SSE with connection pooling and transparent GZIP.

  31. 34

    grpc

    45.4Kgrpc/grpc · C++

    gRPC is a modern, high-performance open-source RPC (remote procedure call) framework that lets client and server applications communicate transparently across languages and platforms.

  32. 35

    ccxt

    44.4Kccxt/ccxt · Python

    CCXT is a unified trading library that connects to 100+ cryptocurrency exchanges and prediction markets through a single API, available in JavaScript/TypeScript, Python, C#, PHP, Go, Java and Rust.

  33. 36

    spark

    44.2Kapache/spark · Scala

    Apache Spark is a unified analytics engine for large-scale data processing, offering high-level APIs in Scala, Java, Python, and R on top of an optimized execution engine.

  34. 37

    retrofit

    43.9Klysine-dev/retrofit · Java

    Retrofit is a type-safe HTTP client for Android and the JVM, created by Square. It lets you define your REST API as a Java/Kotlin interface and turns HTTP calls into simple method calls.

  35. 38

    awesome-system-design-resources

    42.4Kashishps1/awesome-system-design-resources · Java

    A free, curated collection of System Design resources: core concepts, networking and API fundamentals, database and caching basics, distributed systems patterns, and a huge list of interview problems, books, courses, and papers — all aimed at prepping for System Design interviews.

  36. 39

    duckdb

    42.2Kduckdb/duckdb · C++

    DuckDB is a high-performance analytical SQL database system, designed to be fast, reliable, portable and easy to use, with a rich SQL dialect that goes far beyond basic SQL.

  37. 40

    dubbo

    41.6Kapache/dubbo · Java

    Apache Dubbo is an RPC and microservices framework — this repository is its Java implementation. It covers communication, service discovery, traffic management, observability, security, and tooling for building enterprise-grade microservices.

  38. 41

    appsmith

    41.1Kappsmithorg/appsmith · TypeScript

    Appsmith is an open-source low-code platform for building admin panels, internal tools, and dashboards that connect to 25+ databases and any API.

  39. 42

    NewPipe

    40.2KTeamNewPipe/NewPipe · Java

    NewPipe is a free, lightweight streaming front-end for Android: one open-source app for watching videos and listening to audio from YouTube, PeerTube, Bandcamp, SoundCloud and media.ccc.de.

  40. 43

    halo

    39.9Khalo-dev/halo · Java

    Halo is a powerful, easy-to-use open-source website building tool: from personal blogs and knowledge bases to corporate sites and online stores, it aims to cover your site-building needs in one place.

  41. 44

    ruoyi-vue-pro

    39.9KYunaiV/ruoyi-vue-pro · Java

    RuoYi-Vue-Pro is an open-source enterprise admin management system backend built with Spring Boot, MyBatis Plus and Vue/Element, bundled with a WeChat mini-program and optional business modules like Mall, CRM, ERP, OA, MES and IM.

  42. 45

    styleguide

    39.7Kgoogle/styleguide · HTML

    This is a collection of style guides Google uses for its own and Google-originated open-source code, covering languages like C++, Java, Python, Go, JavaScript, TypeScript, HTML/CSS, Shell, Swift, and more.

  43. 46

    MPAndroidChart

    38.2KPhilJay/MPAndroidChart · Kotlin

    MPAndroidChart is a chart/graph view library for Android that supports line, bar, pie, radar, bubble, and candlestick charts, plus scaling, panning, and animations.

  44. 47

    arthas

    37.6Kalibaba/arthas · Java

    Arthas is a Java diagnostic tool from Alibaba that lets developers troubleshoot production issues on a live JVM without modifying code or restarting the server.

  45. 48

    keycloak

    37.4Kkeycloak/keycloak · Java

    Keycloak is an open source Identity and Access Management solution that adds authentication and authorization to applications and services, so you do not need to build your own login, user storage, or permission logic.

  46. 49

    tutorials

    37.3Keugenp/tutorials · Java

    A huge collection of small, focused tutorials for the Java ecosystem - one code module per topic - with a strong focus on Spring, Spring Boot and Spring Security.

  47. 50

    JavaFamily

    37KAobingJava/JavaFamily

    A massive Chinese-language study guide and interview prep collection for Java developers, covering core computer science, Java internals, frameworks, databases, distributed systems, and real interview questions from major Chinese tech companies.

  48. 51

    leetcode

    36.7Kdoocs/leetcode · Java

    A massive collection of LeetCode solutions, plus solutions for two popular Chinese interview prep books (Coding Interviews, 2nd edition and Cracking the Coding Interview, 6th edition), each problem solved in multiple programming languages.

  49. 52

    hello-algorithm

    36.1Kgeekxh/hello-algorithm · Java

    Hello Algorithm (小浩算法) is a free, Chinese-language collection for beginners learning algorithms, bundling illustrated LeetCode solutions, big-tech interview write-ups, open-source ebooks, and mind maps.

  50. 53

    lottie-android

    35.7Kairbnb/lottie-android · Java

    Lottie is a mobile library that parses Adobe After Effects animations exported as JSON via the Bodymovin plugin and renders them natively on Android, iOS, Web, and React Native.

  51. 54

    netty

    35.1Knetty/netty · Java

    Netty is an asynchronous, event-driven network application framework for Java, used to rapidly build maintainable, high-performance protocol servers and clients.

  52. 55

    SmartTube

    35.1Kyuliskov/SmartTube · Java

    SmartTube is a free, open-source media client for Android TVs and TV boxes that lets you browse and play content (mainly YouTube) in a TV-optimized interface, without needing Google Services.

  53. 56

    glide

    35Kbumptech/glide · Java

    A fast, efficient open source media management and image loading framework for Android: it wraps media decoding, memory and disk caching, and resource pooling behind a simple interface.

  54. 57

    selenium

    34.6KSeleniumHQ/selenium · Java

    Selenium is an open-source browser automation framework and ecosystem: you control a real browser from code, mostly to test web apps automatically.

  55. 58

    zxing

    34.2Kzxing/zxing · Java

    ZXing ('Zebra Crossing') is an open-source, multi-format 1D/2D barcode image processing library written in Java, best known for QR Code scanning on Android, with ports to other languages.

  56. 59

    spring-boot-demo

    34.1Kxkcoding/spring-boot-demo · Java

    A large collection of hands-on Spring Boot demos: 66 planned integration modules (55 finished) covering ORM, caching, messaging, security, databases, logging and more, meant for learning Spring Boot by example.

  57. 60

    kafka

    34Kapache/kafka · Java

    Apache Kafka is an open-source distributed event streaming platform used by thousands of companies for high-performance data pipelines, streaming analytics, data integration, and mission-critical applications.

  58. 61

    AndroidUtilCode

    33.6KBlankj/AndroidUtilCode · Java

    AndroidUtilCode is a powerful and easy-to-use library of utility classes for Android development, collecting commonly used helper functions so developers do not have to rewrite them in every project.

  59. 62

    easyexcel

    33.6Kalibaba/easyexcel · Java

    EasyExcel is a Java library from Alibaba for reading and writing Excel files with very low memory usage, solving the out-of-memory problems that plague Apache POI and JXL on large files.

  60. 63

    nacos

    33.5Kalibaba/nacos · Java

    Nacos is a platform from Alibaba for dynamic service discovery, configuration management, and service management, aimed at building cloud-native microservices and AI applications.

  61. 64

    WxJava

    33.2Kbinarywang/WxJava · Java

    WxJava is an open-source Java SDK for WeChat backend development, covering WeChat Pay, the Open Platform, Official Accounts, WeCom (Enterprise WeChat), Channels, and Mini Programs.

  62. 65

    conductor

    32.3Kconductor-oss/conductor · Java

    An open-source durable execution engine for microservices and AI agents: it persists every workflow step so long-running processes survive crashes, retries, and restarts. It originated at Netflix and is maintained by Orkes and the community.

  63. 66

    android-open-project

    31.8KTrinea/android-open-project

    A large categorized collection of notable Android open source projects and libraries, organized by category like views, utility libraries, dev tools, and outstanding developers to help Android developers find reusable components.

  64. 67

    p3c

    30.9Kalibaba/p3c · Kotlin

    Alibaba Java Coding Guidelines (P3C): Java coding rules distilled from the accumulated best practices of Alibaba Group's technical teams, shipped as PMD static-analysis rules and IDE plugins.

  65. 68

    xxl-job

    30.6Kxuxueli/xxl-job · Java

    XXL-JOB is a distributed task scheduling framework: a central scheduler triggers jobs across a cluster of executors, all managed from a web UI. It aims to be quick to develop with, simple to learn, lightweight and easy to extend, and many companies run it in production.

  66. 69

    spring-boot-examples

    30.5Kityouknow/spring-boot-examples · Java

    A collection of small, standalone Spring Boot 3.0 example projects covering common integrations like web, WebFlux, JPA, MyBatis, RabbitMQ, MongoDB, Redis, mail, file upload, and Docker.

  67. 70

    hutool

    30.2Kchinabugotech/hutool · Java

    Hutool calls itself 'a set of tools that keep Java sweet': a rich, easy-to-use Java utility library whose tool classes help you get everyday development tasks done quickly.

  68. 71

    Telegram

    30.1KDrKLO/Telegram · Java

    This is the official open-source Android client for Telegram, a messaging app built for speed and security.

  69. 72

    leakcanary

    30Ksquare/leakcanary · Kotlin

    LeakCanary is a memory leak detection library for Android apps, built by Square.

  70. 73

    apollo

    29.8Kapolloconfig/apollo · Java

    Apollo is a reliable configuration management system. It centrally manages the configurations of different applications and different clusters, and is built for microservice configuration management scenarios.

  71. 74

    canal

    29.7Kalibaba/canal · Java

    Canal is Alibaba's MySQL binlog incremental subscription and consumption component. It disguises itself as a MySQL slave, pulls binlog events from a MySQL master, and lets you consume the parsed changes for things like cache refresh, index building, or database synchronization.

  72. 75

    opendataloader-pdf

    29.7Kopendataloader-project/opendataloader-pdf · Java

    An open-source PDF parser built for AI pipelines: it turns PDFs into Markdown, JSON (with bounding boxes) and HTML, and can auto-tag untagged PDFs into screen-reader-ready Tagged PDFs.

  73. 76

    kestra

    29.7Kkestra-io/kestra · Java

    Kestra is an open-source, event-driven orchestration platform for building data, AI, and infrastructure workflows. You describe them in declarative YAML and manage everything from a built-in web UI.

  74. 77

    Mindustry

    29.4KAnuken/Mindustry · Java

    Mindustry is an automation tower defense RTS written in Java — a game that combines factory-building with tower-defense combat.

  75. 78

    spring-cloud-alibaba

    29.2Kalibaba/spring-cloud-alibaba · Java

    A Spring Cloud toolkit from Alibaba: a one-stop set of components for building distributed Java applications on Alibaba middleware such as Nacos, Sentinel, RocketMQ and Seata.

  76. 79

    SpringAll

    28.9Kwuyouzhuguli/SpringAll · Java

    A large collection of hands-on Spring tutorials in Chinese covering Spring Boot, Spring Boot & Shiro, Spring Batch, Spring Cloud, Spring Cloud Alibaba, and Spring Security & OAuth2, each paired with runnable example code and a companion blog post.

  77. 80

    xgboost

    28.9Kdmlc/xgboost · C++

    XGBoost is an optimized distributed gradient boosting library designed to be highly efficient, flexible and portable — it implements machine learning algorithms under the Gradient Boosting framework.

  78. 81

    linkedin-skill-assessments-quizzes

    28.9KEbazhanov/linkedin-skill-assessments-quizzes · Python

    A free, open-source reference of answers to LinkedIn skill assessment quizzes: questions with the correct answers for tests in JavaScript, React, Python, Git, AWS Lambda, machine learning and more. It has nearly 29,000 GitHub stars.

  79. 82

    semantic-kernel

    28.7Kmicrosoft/semantic-kernel · C#

    Semantic Kernel is a model-agnostic SDK from Microsoft for building, orchestrating, and deploying AI agents and multi-agent systems, from a simple chatbot to complex multi-agent workflows.

  80. 83

    mlflow

    28.4Kmlflow/mlflow · Python

    MLflow is an open source AI engineering platform for agents, LLM apps, and classic ML models: one place to trace, evaluate, monitor, and optimize production AI while controlling costs. It is widely adopted, with over 60 million monthly downloads.

  81. 84

    Chat2DB

    28.3KOtterMind/Chat2DB · Java

    Chat2DB is a free, cross-platform, local-first database client and SQL workspace for developers, DBAs, analysts, and data teams. It combines a full SQL client with an AI assistant that you plug your own model into.

  82. 85

    druid

    28.2Kalibaba/druid · Java

    Druid is an open-source, high-performance Java database connection pool and SQL parser built by Alibaba's DataWorks team. It combines a JDBC connection pool, a multi-dialect SQL parser/AST analyzer, a SQL firewall, and monitoring statistics into one library.

  83. 86

    vhr

    28Klenve/vhr · Java

    This is Vhr (微人事), a human resources management system with a separated front-end and back-end, built with Spring Boot on the backend and Vue on the frontend.

  84. 87

    Ehviewer_CN_SXJ

    27.8Kxiaojieonly/Ehviewer_CN_SXJ · C

    EhViewer is an unofficial Android app for browsing, searching, and downloading galleries from E-Hentai and ExHentai.

  85. 88

    CS-Books

    27.5Kforthespada/CS-Books

    A free, hand-curated collection of over 1,000 classic computer science books plus the author's own study notes, shared as a single GitHub README.

  86. 89

    awesome-low-level-design

    27.4Kashishps1/awesome-low-level-design · Java

    A curated collection of free resources for learning Low Level Design (LLD) / Object-Oriented Design and preparing for LLD interview rounds.

  87. 90

    floci

    26.9Kfloci-io/floci · Java

    Floci is a free, open-source local AWS emulator: it serves AWS-compatible APIs — S3, SQS, DynamoDB, Lambda, ECS and many more — from your own machine for development, testing, and CI, with no cloud account, auth token, or paid feature gates.

  88. 91

    openapi-generator

    26.8KOpenAPITools/openapi-generator · Java

    OpenAPI Generator creates API client libraries (SDKs), server stubs, documentation and configuration files automatically from an OpenAPI spec — versions 2.0 and 3.0 are supported, with 3.1 in beta.

  89. 92

    JCSprout

    26.8KcrossoverJie/JCSprout · Java

    JCSprout ('Java Core Sprout') is a Chinese-language knowledge base of core Java topics: a curated collection of articles on collections, multithreading, JVM internals, distributed systems, frameworks, algorithms and Netty, with over 26k GitHub stars.

  90. 93

    jenkins

    26.7Kjenkinsci/jenkins · Java

    Jenkins is the leading open-source automation server. Built with Java, it takes over the repetitive parts of the development workflow so people can focus on work machines cannot do.

  91. 94

    miaosha

    26.6Kqiurunze123/miaosha · Java

    This is a Chinese learning repository about designing and building a high-concurrency 'flash sale' (seckill) system for internet engineers, combining iterative demo projects, small frameworks, study notes and diagrams covering distributed-systems topics.

  92. 95

    flatbuffers

    26.6Kgoogle/flatbuffers · C++

    FlatBuffers is a cross-platform serialization library built for maximum memory efficiency: you read serialized data directly without a parsing/unpacking step, and it keeps forwards/backwards compatibility.

  93. 96

    flink

    26.4Kapache/flink · Java

    Apache Flink is an open source stream processing framework with powerful stream- and batch-processing capabilities, running your programs on its own distributed runtime.

  94. 97

    A2A

    26.2Ka2aproject/A2A · Shell

    The Agent2Agent (A2A) protocol is an open standard that lets gen AI agents built on different frameworks and run by different companies talk to each other — discovering capabilities, negotiating how to interact, and collaborating on long-running tasks as agents, not just as tools.

  95. 98

    incubator-seata

    26Kapache/incubator-seata · Java

    Apache Seata is an open source distributed transaction solution for microservices, designed to be high-performance and easy to use.

  96. 99

    Apktool

    26KiBotPeaches/Apktool · Java

    Apktool is a command-line tool for reverse engineering third-party, closed, binary Android apps. It decodes an APK's resources to nearly original form and rebuilds the app after you make changes.

  97. 100

    bazel

    26Kbazelbuild/bazel · Java

    Bazel is a fast, scalable, multi-language and extensible build system - one tool that builds and tests software of any size, quickly and reliably.

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