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
    libjpeg-turbo

    libjpeg-turbo

    SIMD-accelerated libjpeg-compatible JPEG codec library

    libjpeg-turbo is a JPEG image codec that uses SIMD instructions (MMX, SSE2, NEON, AltiVec) to accelerate baseline JPEG compression and decompression on x86, x86-64, ARM, and PowerPC systems. On such systems, libjpeg-turbo is generally 2-6x as fast as libjpeg, all else being equal. On other types of systems, libjpeg-turbo can still outperform libjpeg by a significant amount, by virtue of its highly-optimized Huffman coding routines. In many cases, the performance of libjpeg-turbo rivals that of proprietary high-speed JPEG codecs. libjpeg-turbo implements both the traditional libjpeg API as well as the less powerful but more straightforward TurboJPEG API. libjpeg-turbo also features colorspace extensions that allow it to compress from/decompress to 32-bit and big-endian pixel buffers (RGBX, XBGR, etc.), as well as a full-featured Java interface.
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    Downloads: 43,300 This Week
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  • 2
    Recaf

    Recaf

    The modern Java bytecode editor

    Recaf is an open-source Java bytecode editor that simplifies the process of editing compiled Java applications. To make things easier Recaf abstracts away much of the internal class file format. Difficult tasks such as updating stack-frames are done automatically. Along with additional features to assist in the process of editing classes, Recaf is the most feature-rich free bytecode editor available. While Recaf makes bytecode editing a more simple process it does not mean you should dive head-first into editing compiled Java applications without understanding some basic programming concepts and the Java class file architecture.
    Downloads: 204 This Week
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  • 3
    UCanAccess

    UCanAccess

    A pure Java JDBC driver for Microsoft Access database files

    UCanAccess is a pure Java JDBC Driver implementation which allows Java developers and JDBC client programs to read/write Microsoft Access database (.mdb and .accdb) files. No ODBC needed.
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    Downloads: 764 This Week
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  • 4
    JFreeChart
    JFreeChart is a free (LGPL) chart library for the Java(tm) platform. It supports bar charts, pie charts, line charts, time series charts, scatter plots, histograms, simple Gantt charts, Pareto charts, bubble plots, dials, thermometers and more. *** JFreeChart has moved to GitHub: https://github.com/jfree/jfreechart ***
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    Downloads: 378 This Week
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  • 5
    Hacker Scripts

    Hacker Scripts

    Based on a true story

    Hacker Scripts is a cheeky collection of small automation scripts and language ports collected under the tagline “Based on a true story.” The repository gathers playful utilities (originally shell and Ruby scripts) that automate short, real-world tasks — for example, sending a quick “late at work” text when SSH sessions are active, firing off an automated “I’m sick / working from home” email on certain mornings, or even talking to a networked coffee machine to start brewing at precisely the right moment. The README explains the origin story and highlights several canonical scripts and provides usage notes such as required environment variables and cron examples for scheduling. Contributors have provided implementations and ports in many languages and folders (shell, Ruby, Python, Node, Perl, PowerShell, Go, Java, etc.), and the project explicitly welcomes pull requests that add additional language implementations.
    Downloads: 73 This Week
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  • 6
    ZXing

    ZXing

    Barcode scanning library for Java, Android

    ZXing or “Zebra Crossing” is an open source multi-format 1D/2D barcode image processing library that’s been implemented in Java, and also comes with ports to other languages. It currently supports the following formats: UPC-A and UPC-E EAN-8 and EAN-13 Code 39 Code 93 Code 128 ITF Codabar RSS-14 (all variants) RSS Expanded (most variants) QR Code Data Matrix Aztec ('beta' quality) PDF 417 ('alpha' quality) MaxiCode ZXing is made up of several modules, including a core image decoding library, JavaSE-specific client code, and Android client Barcode Scanner. It is the basis of many other third-party open source projects.
    Downloads: 61 This Week
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  • 7
    Aliucord

    Aliucord

    A modification for the Discord Android App

    Aliucord is a modification for the Android Discord app.
    Downloads: 58 This Week
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  • 8
    Autopsy

    Autopsy

    Autopsy® is a digital forensics platform and graphical interface

    Autopsy® is a digital forensics platform and graphical interface to The Sleuth Kit® and other digital forensics tools. It can be used by law enforcement, military, and corporate examiners to investigate what happened on a computer. You can even use it to recover photos from your camera's memory card. Autopsy was designed to be intuitive out of the box. Installation is easy and wizards guide you through every step. All results are found in a single tree. See the intuitive page for more details. Autopsy was designed to be an end-to-end platform with modules that come with it out of the box and others that are available from third-parties.
    Downloads: 58 This Week
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  • 9
    Booklore

    Booklore

    Digital library with smart shelves

    Booklore is a comprehensive self-hosted digital library platform that helps readers organize, manage, track, and even read their personal collections of books and comics from a centralized web interface. It provides powerful metadata management that automatically fetches rich details like titles, authors, covers, and publication info so your library looks organized and beautiful without manual data entry. Users can create smart shelves with custom filters, build dynamic collections that update automatically, and search through thousands of entries instantly, turning chaotic folders of files into a curated reading experience. Booklore supports multi-user access with granular permission controls, making it suitable for families, book clubs, or shared collections, and its built-in reader can display PDFs, EPUBs, and comic formats directly in a browser.
    Downloads: 55 This Week
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  • 10
    EssentialsX

    EssentialsX

    The modern Essentials suite for Spigot and Paper

    EssentialsX is a continuation of the Essentials plugin suite, updated to support modern Minecraft and Spigot versions. It provides countless new features, performance enhancements and fixes that are not available in the original Essentials or Spigot-Essentials. If you're coming from the original Essentials plugin, EssentialsX is a drop-in replacement for Essentials.
    Downloads: 39 This Week
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  • 11
    JSON-java

    JSON-java

    A reference implementation of a JSON package in Java

    JSON is a light-weight language-independent data interchange format. The JSON-Java package is a reference implementation that demonstrates how to parse JSON documents into Java objects and how to generate new JSON documents from the Java classes.
    Downloads: 30 This Week
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  • 12
    Apache Log4j

    Apache Log4j

    Apache Log4j 2 is a versatile, feature-rich, efficient logging API

    Apache Log4j is a versatile, industrial-grade Java logging framework composed of an API, its implementation, and components to assist the deployment for various use cases. Log4j is used by 8% of the Maven ecosystem and listed as one of the top 100 critical open source software projects. The project is actively maintained by a team of several volunteers and supported by a big community.
    Downloads: 23 This Week
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  • 13
    Gson

    Gson

    A Java serialization/deserialization library to convert Java Objects

    Gson is a Java library developed by Google that allows conversion between Java objects and JSON. It enables serialization and deserialization of Java classes to and from JSON format, handling complex and generic types, nulls, custom naming policies, and more. Gson is lightweight, easy to use, and does not require annotation-based configuration, making it a popular choice for JSON processing in Java applications.
    Downloads: 19 This Week
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  • 14
    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.
    Downloads: 79 This Week
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  • 15
    EMV NFC Paycard Enrollment

    EMV NFC Paycard Enrollment

    A Java library used to read and extract data from NFC EMV credit cards

    Java library used to read and extract public data from NFC EMV credit cards.
    Downloads: 17 This Week
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  • 16
    A Java JNA wrapper for Tesseract OCR API
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    Downloads: 107 This Week
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  • 17
    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: 14 This Week
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  • 18
    JOML

    JOML

    A Java math library for OpenGL rendering calculations

    JOML is a high-performance, lightweight math library designed for 3D graphics applications in Java, particularly those using OpenGL, Vulkan, or LWJGL. It provides a complete suite of vector, matrix, quaternion, and geometry operations essential for real-time graphics and game development. Unlike other math libraries, JOML avoids object allocation during calculations, making it highly optimized for garbage-free performance. With precise control over mathematical operations and compatibility with low-level APIs, JOML is a go-to library for Java developers working on real-time 3D engines and simulations.
    Downloads: 13 This Week
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  • 19
    QR Code generator library

    QR Code generator library

    High-quality QR Code generator library in Java, TypeScript/JavaScript

    This project aims to be the best, clearest library for generating QR Codes. My primary goals are flexible options and absolute correctness. The secondary goals are compact implementation size and good documentation comments. This work is an independent implementation based on reading the official ISO specification documents. I believe that my library has a more intuitive API and shorter code length than competing libraries out there. The library is designed first in Java and then ported to TypeScript, Python, Rust, C++, and C. It is open source under the MIT License. For each language, the codebase is roughly 1000 lines of code and has no dependencies other than the respective language’s standard library.
    Downloads: 12 This Week
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  • 20
    International Components for Unicode

    International Components for Unicode

    The home of the ICU project source code

    ICU is a mature, widely used set of C/C++ and Java libraries providing Unicode and Globalization support for software applications. ICU is widely portable and gives applications the same results on all platforms and between C/C++ and Java software. ICU is released under a nonrestrictive open-source license that is suitable for use with both commercial software and with other open-source or free software. Convert text data to or from Unicode and nearly any other character set or encoding. ICU's conversion tables are based on charset data collected by IBM over the course of many decades and is the most complete available anywhere. Compare strings according to the conventions and standards of a particular language, region or country. ICU's collation is based on the Unicode Collation Algorithm plus locale-specific comparison rules from the Common Locale Data Repository, a comprehensive source for this type of data.
    Downloads: 11 This Week
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  • 21
    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: 11 This Week
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  • 22
    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: 10 This Week
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  • 23
    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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  • 24
    tlaplus

    tlaplus

    TLC is an explicit state model checker for specifications in TLA+

    TLC is an explicit state model checker for specifications written in TLA+. The TLA+Toolbox is an IDE for TLA+. TLA+ is a high-level language for modeling programs and systems--especially concurrent and distributed ones. It's based on the idea that the best way to describe things precisely is with simple mathematics. TLA+ and its tools are useful for eliminating fundamental design errors, which are hard to find and expensive to correct in code.
    Downloads: 10 This Week
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  • 25
    MCProtocolLib

    MCProtocolLib

    A library for communication with a Minecraft client/server

    MCProtocolLib is a simple library for communicating with Minecraft clients and servers. It allows developers to build custom bots, clients, or servers for Minecraft with ease.
    Downloads: 9 This Week
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