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
    openHAB Distribution

    openHAB Distribution

    The binary distribution of openHAB

    The open Home Automation Bus (openHAB) project aims to provide a universal integration platform for all things around home automation. It is a pure Java solution, fully based on OSGi. It is designed to be vendor-neutral as well as hardware/protocol-agnostic. openHAB brings together different bus systems, hardware devices, and interface protocols by dedicated bindings. These bindings send and receive commands and status updates on the openHAB event bus. This concept allows designing user interfaces with a unique look&feel, but with the possibility to operate devices based on a big number of different technologies. Besides the user interfaces, it also brings the power of automation logic across different system boundaries.
    Downloads: 5 This Week
    Last Update:
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  • 2
    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: 4 This Week
    Last Update:
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  • 3
    Infinity For Reddit

    Infinity For Reddit

    A Reddit client for Android

    A Reddit client on Android written in Java. It does not have any ads and it features a clean UI and smooth browsing experience. Infinity is a beautiful, feature-rich app that offers a smooth Reddit browsing experience. It is completely free and ad-less; you can browse Reddit without interruptions or distractions. Built by a passionate university student, Infinity is open source.
    Downloads: 4 This Week
    Last Update:
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  • 4
    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: 4 This Week
    Last Update:
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    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: 4 This Week
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  • 6
    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: 4 This Week
    Last Update:
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  • 7
    Swagger Core

    Swagger Core

    Examples, server integrations for generating Swagger API Specification

    Swagger Core is a Java implementation of the OpenAPI Specification. Current version supports JAX-RS2 (javax and jakarta namespaces). One of the common usage scenarios is to integrate swagger-jaxrs2 into an existing or new JAX-RS based project ("code-first"), to automatically provide and expose its APIs definition, which is kept in sync during the project lifecycle. Such definition can be the base for further processing/consumption, including API documentation (e.g with swagger-ui, API client generation in various languages (e.g with swagger-codegen), custom processing, and so on. Such result is achieved by scanning JAX-RS resources and resolving their operations and used types, (also) processing applied annotations (e.g. Swagger, JAX-RS, Jackson, JAXB, etc.). An extension mechanism allows to further customize and pre/post processing result.
    Downloads: 4 This Week
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  • 8
    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: 4 This Week
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  • 9
    libsu

    libsu

    A complete solution for apps using root permissions

    libsu is a modern Android library that provides a safe, convenient API for executing commands with root privileges and interacting with the Android shell. Instead of ad-hoc Runtime.exec calls, it offers structured sessions, proper I/O streams, and lifecycle handling that works reliably across devices. The library focuses on developer ergonomics: thread-safe helpers, Kotlin-friendly APIs, and utilities for file operations, process management, and parcelable data transfer. It’s designed to interoperate smoothly with Magisk-based root environments while degrading gracefully on non-rooted devices when possible. Attention is given to security and correctness—avoiding resource leaks, handling timeouts, and containing elevated operations to explicit scopes. For apps that legitimately need privileged automation or maintenance tasks, libsu becomes the backbone that keeps the “root” parts predictable and testable.
    Downloads: 4 This Week
    Last Update:
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  • 10
    rtmp-rtsp-stream-client-java

    rtmp-rtsp-stream-client-java

    Library to stream in rtmp and rtsp for Android. All code in Java

    Library for streaming in RTMP and RTSP. All code in Java.
    Downloads: 4 This Week
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  • 11
    Sesame

    Sesame

    Java RDF Framework

    This project is no longer actively maintained. It is succeeded by the Eclipse RDF4J project, which can be found at GitHub and at http://www.rdf4j.org/. Sesame is a de-facto standard framework for processing RDF data. This includes parsing, scalable storage, reasoning and full SPARQL 1.1 query/update support. Sesame offers a fully modular toolkit and an easy-to-use Java API that can be connected to all leading RDF storage solutions.
    Downloads: 15 This Week
    Last Update:
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  • 12
    Fetch for Android

    Fetch for Android

    The best file downloader library for Android

    Fetch is a simple, powerful, customizable file download manager library for Android. Simple and easy to use API. If you are saving downloads outside of your application's sandbox, you will need to add the following storage permissions to your application's manifest. For Android SDK version 23(M) and above, you will also need to explicitly request these permissions from the user. Continuous downloading in the background. Concurrent downloading support. Ability to pause and resume downloads. Set the priority of a download. Network-specific downloading support. Ability to retry failed downloads. Ability to group downloads. Easy progress and status tracking. Download remaining time reporting (ETA). Download speed reporting. Save and Retrieve download information anytime. Notification Support. Storage Access Framework, Content Provider and URI support.
    Downloads: 3 This Week
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  • 13
    Hyperion Android

    Hyperion Android

    App Debugging & Inspection Tool for Android

    Hyperion is a hidden plugin drawer that can easily be integrated into any app. The drawer sits discreetly under the app so that it is there when you need it and out of the way when you don't. Hyperion plugins are designed to make inspection of your app quick and simple. Be one of the first to create a third-party plugin. The plugin creation guide is a work in progress, but if you are feeling ambitious you can reference the plugins we have already created. To create your own plugin, implement the Plugin interface and expose the implementation as a service. The plugins made available in this repository leverage Google's AutoService annotation processor to generate the service metadata and simplify the process.
    Downloads: 3 This Week
    Last Update:
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  • 14
    OpenGrok

    OpenGrok

    Fast and usable source code search and cross reference engine

    OpenGrok is a fast and usable source code search and cross reference engine. It helps you search, cross-reference and navigate your source tree. It understands various program file formats and history from many Source Code Management systems. In other words it lets you grok (profoundly understand) source code and is developed in the open, hence the name OpenGrok. It is written in Java.
    Downloads: 3 This Week
    Last Update:
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  • 15
    PSLab Android App

    PSLab Android App

    PSLab Android App

    Repository for the PSLab Android App for performing experiments with the Pocket Science Lab open-hardware platform. This repository holds the Android App for performing experiments with PSLab. PSLab is a tiny pocket science lab that provides an array of equipment for doing science and engineering experiments. It can function like an oscilloscope, waveform generator, frequency counter, programmable voltage and current source and also as a data logger. PSLab is a tiny pocket science lab that provides an array of equipment for doing science and engineering experiments.
    Downloads: 3 This Week
    Last Update:
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  • 16
    mvnd

    mvnd

    Apache Maven Daemon

    Apache Maven is a software project management and comprehension tool. Based on the concept of a project object model (POM), Maven can manage a project's build, reporting and documentation from a central piece of information.
    Downloads: 3 This Week
    Last Update:
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  • 17
    JChart2D

    JChart2D

    jchart2d is a real-time charting library written in java.

    JChart2D is a easy to use component for displaying two- dimensional traces in a coordinate system written in Java. It supports real-time (animated) charting, custom trace rendering, Multithreading, viewports, automatic scaling and labels. Former UI controls (right click context menu, file menu) have been ported to the subproject jchart2d-uimenu (https://sourceforge.net/projects/jchart2d-uimenu.jchart2d.p/) for the benefit of having no dependencies to 3rd party libraries.
    Downloads: 14 This Week
    Last Update:
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  • 18
    CSSBox

    CSSBox

    Pure Java HTML / CSS rendering engine

    CSSBox is an (X)HTML/CSS rendering engine written in pure Java. Its primary purpose is to provide a complete information about the rendered page suitable for further processing. However, it also allows displaying the rendered document.
    Downloads: 17 This Week
    Last Update:
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  • 19
    Android Hidden APIs

    Android Hidden APIs

    A library that provides access to Android hidden APIs

    Android Hidden APIs are classes, methods, and resources that Google hides from you because of stability reasons. These features are hidden because they may be changed on next API version. The internal APIs are located in package com.android.internal and available in the framework.jar, while the hidden APIs are located in the android.jar file with @hide javadoc attribute. Now you know the difference. But I will refer to both as hidden APIs. This repo contains a custom android.jar which you can use to develop your app.
    Downloads: 2 This Week
    Last Update:
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  • 20
    Apache Drill

    Apache Drill

    Apache Drill is a distributed MPP query layer for self describing data

    Apache Drill is a distributed MPP query layer that supports SQL and alternative query languages against NoSQL and Hadoop data storage systems. It was inspired in part by Google's Dremel. Get faster insights without the overhead (data loading, schema creation and maintenance, transformations, etc.) Analyze the multi-structured and nested data in non-relational datastores directly without transforming or restricting the data. Leverage your existing SQL skillsets and BI tools including Tableau, Qlikview, MicroStrategy, Spotfire, Excel and more. Drill supports a variety of NoSQL databases and file systems, including HBase, MongoDB, MapR-DB, HDFS, MapR-FS, Amazon S3, Azure Blob Storage, Google Cloud Storage, Swift, NAS and local files. A single query can join data from multiple datastores. For example, you can join a user profile collection in MongoDB with a directory of event logs in Hadoop.
    Downloads: 2 This Week
    Last Update:
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  • 21
    Asciidoc Editor based on JavaFX 20

    Asciidoc Editor based on JavaFX 20

    Asciidoc Editor and Toolchain written with JavaFX 19

    Asciidoc FX is a WYSIWYG editor for the Asciidoc markup language. You can build PDF, Epub, and HTML books, documents, and slides. Supported Operating Systems and Builds shows the list of available builds with links for reference. If you are looking for the very latest version, visit the link in the note above to be guaranteed of downloading the latest and greatest version of AsciidocFX. AsciidocFX converts documents via the AsciidoctorJ library.
    Downloads: 2 This Week
    Last Update:
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  • 22
    AtlantaFX

    AtlantaFX

    Modern JavaFX CSS theme collection with additional controls

    Modern JavaFX CSS theme collection with additional controls.
    Downloads: 2 This Week
    Last Update:
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  • 23
    Glide

    Glide

    Android image loading & caching library focused on smooth scrolling

    Glide is a fast and efficient open source image loading and caching library for Android that focuses on smooth scrolling. It supports fetching, decoding and displaying images, video stills as well as animated GIFs, with a simple and easy to use interface and API. Glide offers a performant and extensible resource decoding pipeline and automatic resource pooling, and a flexible API that allows developers to plug in to just about any network stack. It is primarily focused on making any type of a list of images as smooth and fast as possible, and is able to achieve this through smart and automatic downsampling and caching, aggressive re-use of resources and deep lifecycle integration. Apart from smooth and speedy scrolling, it’s also good for any case where fetching, resizing, and displaying of a remote image is needed.
    Downloads: 2 This Week
    Last Update:
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  • 24
    Google Maps SDK for Android Samples

    Google Maps SDK for Android Samples

    Samples demonstrating how to use Maps SDK for Android

    Create dynamic, interactive and personalized experiences with maps, locations and geospatial experiences for your Android apps. Create an account, generate an API key, and start creating. Learn how to load the Maps SDK for Android and add a map with a bookmark to your web application. You can customize almost all aspects of the map, such as routes, landforms and places of interest, among others. Find the current location of an Android device and display details of the place or other place of interest in that location. Add bookmarks to a map, interact with click events, customize color and image, and more. Displays an information window with additional data and context when users press a bookmark. Customize user interaction by configuring integrated UI components and gestures. Listen to events on the map, including clicks on maps, clicks on markers, camera changes, and overlay events, among others.
    Downloads: 2 This Week
    Last Update:
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  • 25
    Lagom

    Lagom

    Reactive Microservices for the JVM

    The opinionated microservices framework for moving away from the monolith. Lagom helps you decompose your legacy monolith and build, test, and deploy entire systems of Reactive microservices. Lagom is an open source framework for building systems of Reactive microservices in Java or Scala. Lagom builds on Akka and Play, proven technologies that are in production in some of the most demanding applications today. Lagom's integrated development environment allows you to focus on solving business problems instead of wiring services together. A single command builds the project, starts supporting components and your microservices, as well as the Lagom infrastructure. The build hot-reloads when it detects changes to source code.
    Downloads: 2 This Week
    Last Update:
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