Browse free open source Java Libraries and projects below. Use the toggles on the left to filter open source Java Libraries by OS, license, language, programming language, and project status.

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  • 1
    YCAppTool

    YCAppTool

    Componentized comprehensive case, components are layered into

    YCAppTool is a large Android reference project demonstrating how a growing application can be reorganized into a layered component architecture. It separates infrastructure, reusable functionality, business features, and the main application shell to reduce coupling between teams and modules. The project explores routing, interface-based communication, SPI, reflection, lifecycle initialization, and dependency management between components. Its shared libraries cover storage, logging, permissions, file handling, caching, task scheduling, application state, and other common Android needs. Functional modules add capabilities such as QR scanning, localization, timers, monitoring, media, WebView, and server integration. Extensive documentation explains architectural evolution, common migration problems, dependency pitfalls, stability practices, and diagnostic tooling.
    Downloads: 15 This Week
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  • 2
    Jodd

    Jodd

    Jodd! Lightweight, Java, zero dependencies, use what you like

    Jodd is a set of micro-frameworks and developer-friendly tools and utilities. Code-things-done. Great performances. Tiny dependencies. Use what you like. Welcome to the Jodd, a unique, alternative world of Java. You can find here some micro-frameworks and some handy tools. Nothing more, nothing less. The decision which component is promoted is based on the Maven Central Repo statistics. Version v5 contains remaining libraries and frameworks. They are in maintenance mode.
    Downloads: 14 This Week
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  • 3
    MPAndroidChart

    MPAndroidChart

    A powerful Android chart view / graph view library

    MPAndroidChart is a powerful chart library for Android that offers a beautiful and comprehensive range of charts and graphs. Powerful and very easy to use, it supports the creation of bar-, line-, pie-, bubble-, scatter-, radar- and candlestick charts, as well as scaling, dragging and animations. Charts are rendered cleanly and are visually engaging. Visualizing your data exactly how you want is so much easier with MPAndroidChart. To see more great examples of MPAndroidChart, download the MPAndroidChart Example App on Google Play.
    Downloads: 14 This Week
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  • 4
    red5-server

    red5-server

    Red5 Server core

    Red5 is an Open Source Flash Server written in Java that supports streaming Video (FLV, F4V, MP4, 3GP). Streaming Audio (MP3, F4A, M4A, AAC) Recording Client Streams (FLV and AVC+AAC in FLV container) Shared objects, live stream publishing, remoting, and protocols: RTMP, RTMPT, RTMPS, and RTMPE.
    Downloads: 14 This Week
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    VisualVM

    VisualVM

    VisualVM is an All-in-One Java Troubleshooting Tool

    VisualVM is a visual tool integrating command line JDK tools and lightweight profiling capabilities. Designed for both development and production time use. Use Apache Ant 1.9.9 or above and Oracle JDK 8 to build VisualVM from this repository. VisualVM monitors and troubleshoots applications running on Java 1.4+ from many vendors using various technologies including jvmstat, JMX, Serviceability Agent (SA) and Attach API. VisualVM perfectly fits all the requirements of application developers, system administrators, quality engineers and end users. VisualVM automatically detects and lists locally and remotely running Java applications (jstatd must be running on the remote host). You can also define applications manually by JMX connection. For each process VisualVM shows basic runtime information: PID, main class, arguments passed to java process, JVM version, JDK home, JVM flags and arguments and System properties.
    Downloads: 13 This Week
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  • 6
    AtlantaFX

    AtlantaFX

    Modern JavaFX CSS theme collection with additional controls

    Modern JavaFX CSS theme collection with additional controls.
    Downloads: 10 This Week
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  • 7
    WebDriverManager

    WebDriverManager

    Automated driver management and helper features for Selenium WebDriver

    WebDriverManager is an open-source Java library that carries out the management (i.e., download, setup, and maintenance) of the drivers required by Selenium WebDriver (e.g., chromedriver, geckodriver, msedgedriver, etc.) in a fully automated manner. In addition, WebDriverManager provides other relevant features, such as the capability to discover browsers installed in the local system, building WebDriver objects (such as ChromeDriver, FirefoxDriver, EdgeDriver, etc.), and running browsers in Docker containers seamlessly. The primary use of WebDriverManager is the automation of driver management. For using this feature, you need to select a given manager in the WebDriverManager API (e.g., chromedriver() for Chrome) and invoke the method setup(). The following example shows the skeleton of a test case using JUnit 5, Selenium WebDriver, and WebDriverManager.
    Downloads: 10 This Week
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  • 8
    AnLinux

    AnLinux

    AnLinux allow you to run Linux on Android without root access

    AnLinux allow you to run Linux on Android without root access. The bash script downloads the image over the internet, then decompresses the image, and then mounts it using PRoot.
    Downloads: 9 This Week
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  • 9
    JDA Java Discord API

    JDA Java Discord API

    Java wrapper for the popular chat & VOIP service

    JDA strives to provide a clean and full wrapping of the Discord REST api and its Websocket-Events for Java. This library is a helpful tool that provides the functionality to create a discord bot in java. Discord is currently prohibiting creation and usage of automated client accounts (AccountType.CLIENT). We have officially dropped support for client login as of version 4.2.0! Note that JDA is not a good tool to build a custom discord client as it loads all servers/guilds on startup unlike a client which does this via lazy loading instead. If you need a bot, use a bot account from the Application Dashboard.
    Downloads: 9 This Week
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  • 10
    LWJGL

    LWJGL

    Java library that enables cross-platform access to popular native APIs

    LWJGL is a Java library that enables cross-platform access to popular native APIs useful in the development of graphics (OpenGL, Vulkan), audio (OpenAL) and parallel computing (OpenCL) applications. This access is direct and high-performance, yet also wrapped in a type-safe and user-friendly layer, appropriate for the Java ecosystem. LWJGL is an enabling technology and provides low-level access. It is not a framework and does not provide higher-level utilities than what the native libraries expose. As such, novice programmers are encouraged to try one of the frameworks or game engines that make use of LWJGL, before working directly with the library.
    Downloads: 9 This Week
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  • 11
    dnsjava

    dnsjava

    An implementation of the DNS protocol in Java

    dnsjava is an implementation of DNS in Java. It supports almost all defined record types (including the DNSSEC types), and unknown types. Can be used for queries, zone transfers, and dynamic updates. Includes a cache that can be used by clients, and an authoritative-only server. It supports TSIG authenticated messages, DNSSEC verification, and EDNS0.
    Downloads: 9 This Week
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  • 12
    Java Neural Network Framework Neuroph
    Neuroph is lightweight Java Neural Network Framework which can be used to develop common neural network architectures. Small number of basic classes which correspond to basic NN concepts, and GUI editor makes it easy to learn and use.
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    Downloads: 38 This Week
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  • 13
    iText

    iText

    iText for Java represents the next level of SDKs for developers

    iText for Java represents the next level of SDKs for developers who want to take advantage of the benefits PDF can bring. Equipped with a better document engine, high and low-level programming capabilities and the ability to create, edit, and enhance PDF documents, iText can be a boon to nearly every workflow. iText Suite refers to the complete line of products comprising the open-source iText Core PDF library and its add-ons. The iText Suite is a fully-featured SDK for PDF development that allows you to seamlessly embed extensive PDF functionality into your software or workflows. The iText Suite builds on over a decade of lessons learned from iText 5 (and iTextSharp) development. The latest release of iText, version 8, is a simpler, more performant and extensible library that is ready to handle the increased challenges of today's document workflows, one add-on at a time.
    Downloads: 8 This Week
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  • 14
    Jackcess
    A pure Java library for reading from and writing to MS Access databases.
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    Downloads: 37 This Week
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  • 15
    A Java JNA wrapper for Tesseract OCR API
    Downloads: 45 This Week
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  • 16
    GraphHopper Routing Engine

    GraphHopper Routing Engine

    Open source routing engine for OpenStreetMap

    GraphHopper invests in an active open source community. Our flagships are the GraphHopper routing engine and jsprit, the toolkit for solving rich vehicle routing problems. We promote a fair & diverse mindset. jsprit is a Java based toolkit for solving rich traveling salesman problems (TSP) and vehicle routing problems (VRP). It is lightweight, flexible, easy-to-use, and based on a single all-purpose meta-heuristic. The GraphHopper routing engine is fast and memory-efficient, using Java. It runs server side, offline on Android and iOS. It uses OpenStreetMap data, but can import other data sources as well. GraphHopper is a fast and memory-efficient routing engine released under Apache License 2.0. It can be used as a Java library or standalone web server to calculate the distance, time, turn-by-turn instructions and many road attributes for a route between two or more points. Beyond this "A-to-B" routing it supports "snap to road", Isochrone calculation, mobile navigation and more.
    Downloads: 7 This Week
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  • 17
    Aliucord

    Aliucord

    A modification for the Discord Android App

    Aliucord is a modification for the Android Discord app.
    Downloads: 6 This Week
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  • 18
    ImGui Java

    ImGui Java

    JNI based binding for Dear ImGui

    imgui-java is a comprehensive Java binding for Dear ImGui, the popular immediate-mode GUI library used for real-time tools and debug interfaces. This binding allows Java applications—including those using LWJGL or JOGL—to leverage ImGui’s fast and flexible GUI features without switching languages. With support for native backends and OpenGL rendering, imgui-java is perfect for game engines, development tools, and editors that need an intuitive GUI system. It includes integrations for multiple platforms and rendering contexts, with regular updates to match upstream ImGui releases.
    Downloads: 6 This Week
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  • 19
    tiny-spring

    tiny-spring

    A tiny IoC container refer to Spring

    tiny-spring is a compact educational reimplementation of core Spring Framework concepts for Java developers. It was built to make inversion of control and dependency injection easier to understand than by reading the full Spring codebase. The container supports singleton beans, bean initialization, property injection, and dependency injection between beans. Configuration can be loaded from XML files. The project also implements AspectJ-style AOP with support for interface-based and class-based proxies. Development is organized into milestone Git tags so learners can inspect the framework as features are added step by step. It is intended as a learning project and architectural study rather than a production replacement for Spring.
    Downloads: 6 This Week
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  • 20

    ConcatPDF

    PDF Concatenation Tool

    ConcatPDF is the tool to concatenate PDF files. It can concatenate, extract, encrypt, decrypt, configure PDF files, convert image files to PDF. GUI version and CUI version are both available. iText.NET is iText porting on .NET Framework by J#. This library allows you to generate PDF, (X)HTML, XML, RTF files on Microsoft.NET Framework including ASP.NET.
    Downloads: 38 This Week
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  • 21
    7-Zip-JBinding

    7-Zip-JBinding

    Java wrapper for 7z archiver engine

    Native (JNI) cross-platform library to extract (password protected, multi-part) 7z Zip Rar Tar Split Lzma Iso HFS GZip Cpio BZip2 Z Arj Chm Lhz Cab Nsis Deb Rpm Wim Udf archives and create 7z, Zip, Tar, GZip & BZip2 from Java.
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    Downloads: 39 This Week
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  • 22
    HikariCP

    HikariCP

    A solid, high-performance, JDBC connection pool at last

    HikariCP is a high-performance JDBC connection pooling library designed to offer minimal overhead and maximum throughput. It aims for simplicity and stability, concentrating on fast connection acquisition and minimal latency under load. Its internals manage a pool of connections aggressively but smartly, with options such as leak detection, timeout thresholds, and adaptive connection retirement. Because it avoids heavy internal locking, it scales well in high-concurrency environments, making it a popular choice in microservices and high-throughput web backends. Metrics and instrumentation hooks (for example, via Dropwizard or Micrometer) allow runtime visibility into pool usage and health. HikariCP’s focus is on doing the essential work of pooling correctly and efficiently, rather than bundling extraneous features.
    Downloads: 5 This Week
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  • 23
    JFlex

    JFlex

    The fast scanner generator for Java™ with full Unicode support

    JFlex is a lexical analyzer generator for Java, designed to create fast and efficient scanners. It takes regular expression specifications and produces Java code for tokenizing input text. ​
    Downloads: 5 This Week
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  • 24
    A library help for signing data with PKCS11 token (certificates with SHA1withRSA Sign Algorithm) and create CMS packages. It uses Bouncy Castle Crypto API and SUNPKCS11. Also it verify the signed data and verify signing certificate's OCSP control.
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    Downloads: 130 This Week
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  • 25
    JNativeHook

    JNativeHook

    Global keyboard and mouse listeners for Java

    JNativeHook is a library to provide global keyboard and mouse listeners for Java. This will allow you to listen for global shortcuts or mouse motion that would otherwise be impossible using pure Java. To accomplish this task, JNativeHook leverages platform-dependent native code through Java's native interface to create low-level system-wide hooks and deliver those events to your application.
    Downloads: 4 This Week
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