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: 38,089 This Week
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  • 2
    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: 831 This Week
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  • 3
    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: 179 This Week
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  • 4
    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: 179 This Week
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  • Veeam Data Platform v13.1 Icon
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  • 5
    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: 811 This Week
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  • 6
    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: 65 This Week
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  • 7
    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: 225 This Week
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  • 8
    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: 33 This Week
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  • 9
    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: 31 This Week
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  • Build Agents and Models on One Platform Icon
    Build Agents and Models on One Platform

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  • 10
    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: 31 This Week
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  • 11
    Ollama4j

    Ollama4j

    A simple Java library for interacting with Ollama server

    Ollama4j is a lightweight Java library designed to simplify interaction with the Ollama server, enabling developers to integrate locally hosted large language models into Java applications with minimal friction. It provides a clean and developer-friendly API that abstracts the underlying REST communication, allowing users to focus on building features rather than handling low-level networking details. The library supports a wide range of core capabilities, including chat-based interactions, text generation, embeddings, and model management, making it suitable for both simple applications and more advanced AI-driven systems. It integrates seamlessly into Java ecosystems through Maven or Gradle dependencies, and it works with standard Java environments starting from JDK 11 and above. Ollama4j also includes support for advanced features such as tool or function calling, enabling models to interact with external systems and execute more complex workflows.
    Downloads: 26 This Week
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  • 12
    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: 19 This Week
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  • 13
    Event Ruler

    Event Ruler

    Java library that allows matching many thousands of Events per second

    Event Ruler (called Ruler in the rest of the doc for brevity) is a Java library that allows matching Rules to Events. An event is a list of fields, which may be given as name/value pairs or as a JSON object. A rule associates event field names with lists of possible values. Event Ruler is a Java library that allows matching many thousands of Events per second to any number of expressive and sophisticated rules.
    Downloads: 18 This Week
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  • 14
    PSI Probe

    PSI Probe

    Advanced manager and monitor for Apache Tomcat

    Advanced manager and monitor for Apache Tomcat, forked from Lambda Probe. Generally supported versions for third-party tomcat providers align with their support but earlier versions may still work. It is advisable in every case to use only supported tomcat releases per specific vendor. Our support will only be against non-CVE releases.
    Downloads: 17 This Week
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  • 15
    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: 17 This Week
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  • 16
    Epic

    Epic

    Dynamic java method AOP hook for Android

    Epic is a project focused on enabling advanced runtime modifications and enhancements within Android environments, particularly around system behavior and application interaction. It provides tools for hooking and manipulating methods at runtime, allowing developers to intercept and modify application logic dynamically. The framework is designed to work alongside other system-level tools, enabling deeper customization and experimentation. It is commonly used in reverse engineering, debugging, and feature extension scenarios. Epic emphasizes flexibility and control over application execution flow. Its architecture allows developers to explore internal behaviors without modifying original binaries. It serves as a powerful tool for advanced Android development and research.
    Downloads: 15 This Week
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  • 17
    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: 15 This Week
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  • 18
    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: 15 This Week
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  • 19
    ProgressManager

    ProgressManager

    Listen the progress of downloading and uploading in Okhttp

    ProgressManager is an Android networking utility designed to monitor and manage upload and download progress for HTTP requests built with OkHttp. The library simplifies the implementation of progress tracking in Android applications by wrapping request and response bodies with listeners that report transfer status in real time. It is especially useful for applications that handle file uploads, media downloads, or large network transfers where users expect visible progress feedback. The project supports integration with Glide and other Android networking workflows, enabling developers to track image loading and resource downloads without extensive boilerplate code. Its architecture emphasizes minimal intrusion into existing networking stacks while maintaining compatibility with common Android development patterns. ProgressManager is widely used in applications requiring responsive file transfer interfaces and efficient network progress monitoring.
    Downloads: 15 This Week
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  • 20
    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: 15 This Week
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  • 21
    RetrofitUrlManager

    RetrofitUrlManager

    Let Retrofit support multiple baseUrl and can be change the baseUrl

    RetrofitUrlManager is an Android networking utility built on top of Retrofit and OkHttp that enables applications to support multiple base URLs and dynamically switch endpoints at runtime. The library simplifies complex networking architectures where apps interact with multiple APIs, environments, or microservices without requiring developers to rebuild Retrofit instances manually. It works by intercepting outgoing requests and replacing or modifying the target domain through a centralized management layer. The project is especially useful in modular Android applications, debugging environments, multi-tenant systems, and apps requiring dynamic API routing. RetrofitUrlManager integrates seamlessly into existing Retrofit workflows with minimal configuration while preserving compatibility with OkHttp interceptors and Retrofit annotations. Its design prioritizes flexibility, runtime configurability, and reduced boilerplate in Android networking stacks.
    Downloads: 15 This Week
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  • 22
    Spring AI

    Spring AI

    An Application Framework for AI Engineering

    Spring AI is a framework within the Spring ecosystem that simplifies the integration of artificial intelligence capabilities into Java applications by providing abstractions over various AI services and models. It is designed to align with familiar Spring development patterns, allowing developers to incorporate AI features such as chat, embeddings, and prompt handling using consistent APIs. The framework supports multiple providers, including OpenAI, Azure OpenAI, and other compatible services, enabling flexibility in deployment strategies. It focuses on production readiness by offering features such as configuration management, observability, and integration with Spring Boot applications. Spring AI also includes support for retrieval-augmented generation, enabling applications to connect language models with structured and unstructured data sources. Its architecture encourages modular design, making it easier to extend or swap components without rewriting large parts of the system.
    Downloads: 15 This Week
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  • 23
    XUI

    XUI

    A simple and elegant Android native UI framework

    XUI is a lightweight Android native UI framework that provides a comprehensive set of components and design styles to simplify mobile interface development. It aims to reduce the complexity of building Android UIs by offering a unified and consistent design system with ready-to-use components. The library includes a wide range of UI elements such as buttons, text inputs, dialogs, pickers, navigation bars, and more, covering most common development needs. It is designed to be easy to integrate and use, with simplified APIs that allow developers to implement features quickly without extensive boilerplate code. XUI also emphasizes visual consistency by providing predefined themes and styling options that ensure a cohesive look across applications. Despite its broad functionality, it maintains a relatively small footprint, making it efficient for mobile environments. Overall, XUI is a practical toolkit for accelerating Android UI development while maintaining quality and consistency.
    Downloads: 15 This Week
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  • 24
    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: 14 This Week
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  • 25
    Jackcess
    A pure Java library for reading from and writing to MS Access databases.
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    Downloads: 63 This Week
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