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.

  • Collect! is a highly configurable debt collection software Icon
    Collect! is a highly configurable debt collection software

    Everything that matters to debt collection, all in one solution.

    The flexible & scalable debt collection software built to automate your workflow. From startup to enterprise, we have the solution for you.
    Learn More
  • Inventory and Order Management Software for Multichannel Sellers Icon
    Inventory and Order Management Software for Multichannel Sellers

    Avoid stockouts, overselling, and losing control as your business grows.

    We are the most powerful inventory and order management platform for Amazon, Walmart, and multichannel product sellers. Centralize orders, product information, and fulfillment operations to run more efficiently, sell more products, and stay compliant with marketplace requirements so you can grow profitably.
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  • 1
    PhotoView

    PhotoView

    Implementation of ImageView for Android that supports zooming

    PhotoView is an Android library that extends the ImageView widget to support zooming, panning, and scaling gestures with ease. Designed to be lightweight and intuitive, PhotoView provides advanced image manipulation features without requiring complex configuration. It integrates seamlessly into Android apps and is commonly used in galleries, document viewers, and photo browsers where pinch-to-zoom and drag gestures are needed.
    Downloads: 9 This Week
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  • 2
    ScribeJava

    ScribeJava

    Simple OAuth library for Java

    Welcome to the home of ScribeJava, the simple OAuth client Java lib! That single line (added newlines for readability) is the only thing you need to configure ScribeJava with LinkedIn's OAuth API for example.
    Downloads: 9 This Week
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  • 3
    jCasbin

    jCasbin

    An authorization library that supports access control models

    An authorization library that supports access control models like ACL, RBAC, ABAC for Golang, Java, C/C++, Node.js, Javascript, PHP, Laravel, Python, .NET (C#), Delphi, Rust, Ruby, Swift (Objective-C), Lua (OpenResty), Dart (Flutter) and Elixir. In Casbin, an access control model is abstracted into a CONF file based on the PERM metamodel (Policy, Effect, Request, Matchers). So switching or upgrading the authorization mechanism for a project is just as simple as modifying a configuration. Besides memory and file, Casbin policy can be stored into lots of places. Currently, dozens of databases are supported, from MySQL, Postgres, Oracle to MongoDB, Redis, Cassandra, AWS S3. jCasbin is a powerful and efficient open-source access control library for Java projects. It provides support for enforcing authorization based on various access control models.
    Downloads: 9 This Week
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  • 4
    uCrop

    uCrop

    Image cropping library for Android

    We develop lots of different Android apps at Yalantis, and our experience shows that almost every application we deal with needs image cropping functionality. Image cropping can be used for various purposes, from ordinary adjustment of user profile images to more complex features that involve aspect ratio cropping and flexible image transformations. Since we want to provide all our customers with the best set of tools for image editing functionality, we decided to create uCrop, an image cropping library for Android. You might be wondering why we couldn’t just use one of the existing solutions for image cropping for Android. After all, you can find lots of them on Github and on the Android Arsenal. But here is the thing, none of these solutions could satisfy our requirements. Let’s take a quick look at the most popular open-source image cropping libraries and explain why they don’t quite fit the bill.
    Downloads: 9 This Week
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  • The AI workplace management platform Icon
    The AI workplace management platform

    Plan smart spaces, connect teams, manage assets, and get insights with the leading AI-powered operating system for the built world.

    By combining AI workflows, predictive intelligence, and automated insights, OfficeSpace gives leaders a complete view of how their spaces are used and how people work. Facilities, IT, HR, and Real Estate teams use OfficeSpace to optimize space utilization, enhance employee experience, and reduce portfolio costs with precision.
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  • 5
    Alpakka Kafka

    Alpakka Kafka

    Alpakka is a Reactive Enterprise Integration library for Java

    The Alpakka project is an open source initiative to implement stream-aware and reactive integration pipelines for Java and Scala. It is built on top of Akka Streams and has been designed from the ground up to understand streaming natively and provide a DSL for reactive and stream-oriented programming, with built-in support for backpressure. Akka Streams is a Reactive Stream and JDK 9+ java.util.concurrent.Flow-compliant implementation and therefore fully interoperable with other implementations. As Kafka’s client protocol negotiates the version to use with the Kafka broker, you may use a Kafka client version that is different than the Kafka broker’s version.
    Downloads: 8 This Week
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  • 6
    AndroidAudioConverter

    AndroidAudioConverter

    Convert audio files inside your Android app easily

    Convert audio files inside your Android app easily. This is a wrapper of FFmpeg-Android-Java lib.
    Downloads: 8 This Week
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  • 7
    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: 8 This Week
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  • 8
    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: 8 This Week
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  • 9
    Brave

    Brave

    Java distributed tracing implementation compatible with Zipkin backend

    Brave is a distributed tracing instrumentation library. Brave typically intercepts production requests to gather timing data, correlate and propagate trace contexts. While typically trace data is sent to Zipkin server, third-party plugins are available to send to alternate services such as Amazon X-Ray. This repository includes dependency-free Java libraries and instrumentation for common components used in production services. For example, this includes trace filters for Servlet and log correlation for Apache Log4J. Brave's dependency-free tracer library works against JRE6+. This is the underlying api that instrumentation use to time operations and add tags that describe them. This library also includes code that parses X-B3-TraceId headers.
    Downloads: 8 This Week
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  • Field Service+ for MS Dynamics 365 & Salesforce Icon
    Field Service+ for MS Dynamics 365 & Salesforce

    Empower your field service with mobility and reliability

    Resco’s mobile solution streamlines your field service operations with offline work, fast data sync, and powerful tools for frontline workers, all natively integrated into Dynamics 365 and Salesforce.
    Learn More
  • 10
    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: 8 This Week
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  • 11
    Heritrix

    Heritrix

    Internet Archive's open-source, web-scale, web crawler project

    Heritrix is the Internet Archive's open-source, extensible, web-scale, archival-quality web crawler project. Heritrix (sometimes spelled heretrix, or misspelled or missaid as heratrix/heritix/heretix/heratix) is an archaic word for heiress (woman who inherits). Since our crawler seeks to collect and preserve the digital artifacts of our culture for the benefit of future researchers and generations, this name seemed apt. Heritrix is designed to respect the robots.txt exclusion directives† and META nofollow tags. Please consider the load your crawl will place on seed sites and set politeness policies accordingly. Also, always identify your crawl with contact information in the User-Agent so sites that may be adversely affected by your crawl can contact you or adapt their server behavior accordingly.
    Downloads: 8 This Week
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  • 12
    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: 8 This Week
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  • 13
    Java Tablesaw

    Java Tablesaw

    Java dataframe and visualization library

    Tablesaw is a dataframe and visualization library that supports loading, cleaning, transforming, filtering, and summarizing data. If you work with data in Java, it may save you time and effort. Tablesaw also supports descriptive statistics and can be used to prepare data for working with machine learning libraries like Smile, Tribuo, H20.ai, DL4J. Import data from RDBMS, Excel, CSV, TSV, JSON, HTML, or Fixed Width text files, whether they are local or remote (http, S3, etc.) Tablesaw supports data visualization by providing a wrapper for the Plot.ly JavaScript plotting library. Here are a few examples of the new library in action. Descriptive stats: mean, min, max, median, sum, product, standard deviation, variance, percentiles, geometric mean, skewness, kurtosis, etc. Add tablesaw-core to your project. You can find the version number for the latest release in the release notes.
    Downloads: 8 This Week
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  • 14
    Official Android SDK for Stream Chat

    Official Android SDK for Stream Chat

    Android Chat SDK ➜ Stream Chat API. UI component libraries for chat

    This is the official Android SDK for Stream Chat, a service for building chat and messaging applications. This library includes both a low-level chat SDK and a set of reusable UI components. Most users start with the UI components and fall back to the lower-level API when they want to customize things. We're proud to say that we're the first Android Chat SDK that supports Jetpack Compose! We released our Compose UI Components one day after the official Jetpack Compose 1.0 release and our team members have been working hard on it since then. Now it's mature and stable enough for us to officially recommend it for all new applications and all modern chat implementations. If you're looking for something highly customizable and extremely performant, check out our Compose SDK.
    Downloads: 8 This Week
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  • 15
    jvm-mon

    jvm-mon

    Console-based JVM monitoring tool

    Console-based JVM monitoring - when you just want to SSH into a server and see what’s going on. jvm-top lets you monitor your JVM server applications from the terminal.
    Downloads: 8 This Week
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  • 16
    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: 8 This Week
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  • 17
    Importer library to import assets from different common 3D file formats such as Collada, Blend, Obj, X, 3DS, LWO, MD5, MD2, MD3, MDL, MS3D and a lot of other formats. The data is stored in an own in-memory data-format, which can be easily processed. www.open3mod.com/ is a 3D model viewer and exporter based on Assimp that is also Open Source.
    Downloads: 34 This Week
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  • 18
    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: 35 This Week
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  • 19

    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.
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    Downloads: 48 This Week
    Last Update:
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  • 20
    AndroidAudioRecorder

    AndroidAudioRecorder

    A fancy audio recorder lib for Android. Supports WAV format at 48kHz

    A fancy audio recorder lib for Android. Supports WAV format at 48kHz.
    Downloads: 7 This Week
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  • 21
    Autobahn|Java

    Autobahn|Java

    WebSocket & WAMP in Java for Android and Java 8

    Client library providing WAMP on Java 8 (Netty) and Android, plus (secure) WebSocket for Android. The WebSocket layer is using a callback-based user API, and is specifically written for Android. Eg it does not run any network stuff on the main (UI) thread. The WAMP layer is using Java 8 CompletableFuture for WAMP actions (call, register, publish, and subscribe) and the Observer pattern for WAMP session, subscription and registration lifecycle events. The library is MIT licensed, maintained by the Crossbar.io Project, tested using the AutobahnTestsuite and published as a JAR to Maven and as a Docker toolchain image to Dockerhub.
    Downloads: 7 This Week
    Last Update:
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  • 22
    ButterKnife

    ButterKnife

    Bind Android views and callbacks to fields and methods

    ButterKnife is an annotation-based view binding library for Android that reduces boilerplate in Activities, Fragments, and custom views. Developers replace repetitive findViewById calls with BindView fields and define UI event handlers using annotations like @OnClick, with the library generating efficient binding code at compile time. Because it relies on annotation processing, there’s no reflection at runtime, keeping startup paths lean and predictable. The generated bind/unbind lifecycle helps avoid memory leaks by clearing references when views are destroyed. Butter Knife made UI code more readable and maintainable for years, especially in large codebases with complex layouts and many event hooks. While newer Android APIs now offer official view binding alternatives, the project remains a landmark example of how code generation can simplify everyday Android development.
    Downloads: 7 This Week
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  • 23
    Dropwizard

    Dropwizard

    Simple library for building production-ready RESTful web services

    Dropwizard is a Java framework for developing ops-friendly, high-performance, RESTful web services. Dropwizard pulls together stable, mature libraries from the Java ecosystem into a simple, light-weight package that lets you focus on getting things done. Dropwizard has out-of-the-box support for sophisticated configuration, application metrics, logging, operational tools, and much more, allowing you and your team to ship a production-quality web service in the shortest time possible. Dropwizard straddles the line between being a library and a framework. Its goal is to provide performant, reliable implementations of everything a production-ready web application needs. Because this functionality is extracted into a reusable library, your application remains lean and focused, reducing both time-to-market and maintenance burdens.
    Downloads: 7 This Week
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  • 24
    EasyDeviceInfo

    EasyDeviceInfo

    [Android Library] Get device information in a super easy way

    Android library to get device information in a super easy way. The library is built for simplicity and approachability. It not only eliminates most boilerplate code for dealing with device information but also provides an easy and simple API to retrieve them. EasyDeviceInfo is split into multiple module-libraries, v2.2.0 onwards. Use the appropriate one as per your requirement.
    Downloads: 7 This Week
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  • 25
    Fresco

    Fresco

    An Android library for managing images and the memory they use

    Fresco’s image pipeline will load images from the network, local storage, or local resources. To save data and CPU, it has three levels of cache; two in memory and another in internal storage. Fresco’s Drawee shows a placeholder for you until the image has loaded and then automatically shows the image when it arrives. When the image goes off-screen, it automatically releases its memory. A decompressed image - an Android Bitmap - takes up a lot of memory. This leads to more frequent runs of the Java garbage collector. This slows apps down. The problem is especially bad without the improvements to the garbage collector made in Android 5.0. On Android 4.x and lower, Fresco puts images in a special region of Android memory. It also makes sure that images are automatically released from memory when they’re no longer shown on screen. This lets your application run faster - and suffer fewer crashes.
    Downloads: 7 This Week
    Last Update:
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