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.

  • 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
  • Failed Payment Recovery for Subscription Businesses Icon
    Failed Payment Recovery for Subscription Businesses

    For subscription companies searching for a failed payment recovery solution to grow revenue, and retain customers.

    FlexPay’s innovative platform uses multiple technologies to achieve the highest number of retained customers, resulting in reduced involuntary churn, longer life span after recovery, and higher revenue. Leading brands like LegalZoom, Hooked on Phonics, and ClinicSense trust FlexPay to recover failed payments, reduce churn, and increase customer lifetime value.
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  • 1
    RE2/J

    RE2/J

    linear time regular expression matching in Java

    RE2/J is a high-performance regular expression engine implemented in pure Java as a port of Google’s C++ RE2 library. Unlike traditional regex engines such as Java’s java.util.regex, PCRE, or Perl’s implementation—which rely on backtracking and can suffer from catastrophic exponential runtimes—RE2/J guarantees linear-time matching relative to input size. It achieves this efficiency by simulating all possible matches in a single pass using a nondeterministic finite automaton (NFA), ensuring predictable and safe performance even with complex patterns. This makes RE2/J ideal for applications that must handle user-supplied regular expressions securely without the risk of denial-of-service through regex backtracking. While it omits some advanced features like backreferences and certain Java regex options, it supports the vast majority of practical expressions used in production code. RE2/J thus provides a reliable, safe, and scalable alternative for developers.
    Downloads: 1 This Week
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  • 2
    RoaringBitmap

    RoaringBitmap

    A better compressed bitset in Java

    Bitsets, also called bitmaps, are commonly used as fast data structures. Unfortunately, they can use too much memory. To compensate, we often use compressed bitmaps. Roaring bitmaps are compressed bitmaps which tend to outperform conventional compressed bitmaps such as WAH, EWAH or Concise. In some instances, roaring bitmaps can be hundreds of times faster and they often offer significantly better compression. They can even be faster than uncompressed bitmaps.
    Downloads: 1 This Week
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  • 3
    RoundCornerProgressBar

    RoundCornerProgressBar

    [Android] Round Corner Progress Bar Library for Android

    Round corner is cool. Let's make your progress bar with round corner. Colorful rounded corner progress bar.
    Downloads: 1 This Week
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  • 4
    Subsampling Scale Image View

    Subsampling Scale Image View

    Deep zoom view for displaying huge images without loss of detail

    Android library (AAR). Highly configurable, easily extendable deep zoom view for displaying huge images without loss of detail. Perfect for photo galleries, maps, building plans etc. A custom image view for Android, designed for photo galleries and displaying huge images (e.g. maps and building plans) without OutOfMemoryErrors. Includes pinch to zoom, panning, rotation and animation support, and allows easy extension so you can add your own overlays and touch event detection. The view optionally uses subsampling and tiles to support very large images - a low resolution base layer is loaded and as you zoom in, it is overlaid with smaller high resolution tiles for the visible area. This avoids holding too much data in memory. It's ideal for displaying large images while allowing you to zoom in to the high resolution details. You can disable tiling for smaller images and when displaying a bitmap object.
    Downloads: 1 This Week
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  • The full-stack observability platform that protects your dataLayer, tags and conversion data Icon
    The full-stack observability platform that protects your dataLayer, tags and conversion data

    Stop losing revenue to bad data today. and protect your marketing data with Code-Cube.io.

    Code-Cube.io detects issues instantly, alerts you in real time and helps you resolve them fast. No manual QA. No unreliable data. Just data you can trust and act on.
    Learn More
  • 5
    Telegram Bot Java Library

    Telegram Bot Java Library

    Java library to create bots using Telegram Bots API

    A simple-to-use library to create Telegram Bots in Java.
    Downloads: 1 This Week
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  • 6
    TwelveMonkeys

    TwelveMonkeys

    Additional plug-ins and extensions for Java's ImageIO

    TwelveMonkeys ImageIO provides extended image file format support for the Java platform, through plugins for the javax.imageio. package. The main goal of this project is to provide support for formats not covered by the JRE itself. Support for these formats is important, to be able to read data found "in the wild", as well as to maintain access to data in legacy formats. As there is lots of legacy data out there, we see the need for open implementations of readers for popular formats.
    Downloads: 1 This Week
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  • 7
    Valkey GLIDE

    Valkey GLIDE

    An open source Valkey client library that supports Valkey and Redis

    Valkey General Language Independent Driver for the Enterprise (GLIDE), is an open-source Valkey client library. Valkey GLIDE is one of the official client libraries for Valkey, and it supports all Valkey commands. Valkey GLIDE supports Valkey 7.2 and above, and Redis open-source 6.2, 7.0 and 7.2. Application programmers use Valkey GLIDE to safely and reliably connect their applications to Valkey- and Redis OSS- compatible services. Valkey GLIDE is designed for reliability, optimized performance, and high-availability, for Valkey and Redis OSS-based applications. It is sponsored and supported by AWS, and is pre-configured with best practices learned from over a decade of operating Redis OSS-compatible services used by hundreds of thousands of customers. To help ensure consistency in application development and operations, Valkey GLIDE is implemented using a core driver framework, written in Rust, with language-specific extensions.
    Downloads: 1 This Week
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  • 8
    WebRTC Android

    WebRTC Android

    webrtc VideoCall VideoConference

    WebRTC Android is a sample project that showcases how to implement real-time peer-to-peer communication (audio, video, and data) on Android using WebRTC. It demonstrates a complete pipeline—from signaling and connection setup to media capture and transmission—making it an excellent reference for developers looking to integrate WebRTC into their mobile apps. The project includes UI components and handles network state changes, codec configuration, and ICE negotiation to provide a robust base for real-world applications.
    Downloads: 1 This Week
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  • 9
    Xabber

    Xabber

    Open-source XMPP client for Android

    Open source Jabber (XMPP) client with multi-account support, clean and simple interface. Being both free (as in freedom!) and ad-free, Xabber is designed to be the best Jabber client for Android. Xabber uses Gradle build system. The only specific thing is git submodule for the MemorizingTrustManager library. Since it’s inception in 2011, Xabber has grown to be a number one XMPP client for Android. It is fast, reliable and packed with lots of features that make it more advanced than most desktop clients. Xabber interface was perfected over many years to give a very clear yet informative presentation of your contacts and chats. Great amount of details are shown in a subtle way to not obscure your view. Internet connection is not as reliable as we’d like on mobile networks, users often experience connection loss. Xabber for Android was optimized to ensure low battery usage and to quickly reconnect.
    Downloads: 1 This Week
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  • AestheticsPro Medical Spa Software Icon
    AestheticsPro Medical Spa Software

    Our new software release will dramatically improve your medspa business performance while enhancing the customer experience

    AestheticsPro is the most complete Aesthetics Software on the market today. HIPAA Cloud Compliant with electronic charting, integrated POS, targeted marketing and results driven reporting; AestheticsPro delivers the tools you need to manage your medical spa business. It is our mission To Provide an All-in-One Cutting Edge Software to the Aesthetics Industry.
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  • 10
    compileflow

    compileflow

    Core business process engine of Alibaba Halo platform

    Compileflow is a very lightweight, high-performance, integrable and extensible process engine. The Compileflow process engine is an important part of Taobao Business Process Management(TBBPM), which is dedicated to optimizating operations at Alibaba’s Taobao Marketplace. Specifically, Compileflow is designed to focus on pure memory execution and stateless process engines by converting process files to generate, compile and execute java code. Currently, compileflow powers multiple core systems such as Alibaba's e-commerce stores and transactions. Compileflow allows developers to design their own business processes through the process editor, which will visualize complex business logic, and build a bridge between designers and development engineers.
    Downloads: 1 This Week
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  • 11
    react-native-geolocation

    react-native-geolocation

    Geolocation APIs for React Native

    The Geolocation API module for React Native extends the Geolocation web spec.
    Downloads: 1 This Week
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  • 12
    springdoc-openapi

    springdoc-openapi

    Library for OpenAPI 3 with spring-boot

    An extended support for springdoc-openapi v1 project is now available for organizations that need support beyond 2023. The springdoc-openapi Java library helps automating the generation of API documentation using Spring Boot projects. springdoc-openapi works by examining an application at runtime to infer API semantics based on Spring configurations, class structure and various annotations. The library automatically generates documentation in JSON/YAML and HTML formatted pages. The generated documentation can be complemented using swagger-api annotations.
    Downloads: 1 This Week
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  • 13
    Early Access iText, a PDF generation library in Java
    Downloads: 14 This Week
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  • 14
    silvertunnel - Java lib+browser for TOR
    silvertunnel.org is a project that provides an end-user browser, a Java library and additional Java security tools to easily access anonymity networks such as the Tor (torproject.org) network. Secure and easy to use. Tor4Java and Tor Browser. Attention: see project status on page https://sourceforge.net/p/silvertunnel/discussion/962278/thread/83dc2d02/#
    Downloads: 8 This Week
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  • 15
    GLPK for Java

    GLPK for Java

    Java language binding for the GNU Linear Programming Kit (GLPK)

    GLPK for Java provides a Java language binding for the library GLPK. GLPK is a proven solver for linear and mixed integer mathematical programming problems. For Windows binaries see project GLPK for Windows (http://sourceforge.net/projects/winglpk/).
    Downloads: 17 This Week
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  • 16
    An open source Java implementation to interpret and render Computer Graphics Metafile (CGM) graphics files.
    Downloads: 9 This Week
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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: 3 This Week
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  • 18
    ANDS PID Client
    ANDS PID Client is a generic Java client library for accessing the ANDS Persistent Identifier service and the Digital Object Identifier Service. Written by CSIRO Australia and funded by the ANDS Australian Research Data Commons Project .
    Downloads: 8 This Week
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  • 19
    The ftp4j library implements a Java full-featured FTP client. With ftp4j embedded in your application you can: transfer files (upload and download), browse the FTP site (directory listing), create, delete, rename and move directories and files.
    Downloads: 4 This Week
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  • 20
    JME (Java Math Expression)

    JME (Java Math Expression)

    Evaluador de expresiones matemáticas para Java en español

    Biblioteca para Java que implementa un potente evaluador matemático en español y un lenguaje estructurado de script, JMEScript, que hace uso de éste. Puede evaluar expresiones altamente complejas, que incluyen; * vectores * matrices * números complejos * números enteros y reales de precisión arbitraria, * expresiones booleanas * conjuntos * cadenas * diccionarios * grafos * correspondencias y relaciones finitas Permite especificar operaciones y funciones definidas por el usuario además de incluir más de 60 operadores predefinidos y más de 450 funciones predefinidas. También implementa un potente modo REPL que permite usar interactivamente la mayoría de características del lenguaje implementado por la biblioteca JME, incluida la importación y exportación CSV, HTML, JSON y XML. Puede consultarse la documentación de usuario y de desarrollador en la página https://miguelalejandromorenobarrientos.github.io/JmeDoc/ IDE JMEScriptGUI https://sourceforge.net/projects/j
    Downloads: 11 This Week
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  • 21
    Coronis SDK

    Coronis SDK

    Set of module for data processing of wireless device

    The goal is to create a leading “Set of software libraries for data processing of wireless device based on Coronis platform“. These libraries will run on all major platforms (embedded and desktop) and provide services for data processing through generic APIs. Keywords: Coronis, Wavenis, API, Plugin, Wireless, Waveport, Wavecard, Profile, Java, C, C++, C#
    Downloads: 3 This Week
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  • 22
    Snippetory

    Snippetory

    Java templating solution with passive templates.

    Snippetory is a platform for java developers dealing with any text generation. The abstraction layer helps to keep the issues of the 'view' in the view, while all logic is implemented in java. Editing, debugging and testing, all with the tools one is already used to. The separation of template keeps the template simple, the logic compact, and easy to navigate, and offers completely new re-usage scenarios. Sourceforge code hosting is abandoned. Primary site is now https://gitlab.com/jproggy/Snippetory
    Downloads: 10 This Week
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  • 23
    openSCADA

    openSCADA

    openSCADA® is an open source SCADA system written in JAVA

    openSCADA is an open source Supervisory Control And Data Acquisition System. It is platform independent and based on a modern system design that provides security and flexibility at the same time. openSCADA is flexible. It is not an out of the box solution, but a set of tools that can be combined in many different ways. It provides development libraries, interface applications, mass configuration tools, front-end and back-end applications. openSCADA is ready to rock. It is used 24/7 in several installations around this world. openSCADA is supported. So if you prefer a fully supported, out of the box instead of a “build it yourself” solution you can contact IBH SYSTEMS GmbH and let us do the job. If you like, you will still get the source code that was developed specially for you. openSCADA needs you. Writing source code, writing documentation, fixing bugs or providing fresh input. Anything is welcome.
    Downloads: 10 This Week
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  • 24
    The OpenHMS Project
    OpenHMS brands a collection of projects and many subprojects developed by Health Market Science. This is a robust collection of development libraries, APIs, and tools oriented around data manipulation and professional software development.
    Downloads: 9 This Week
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  • 25
    The JAVE (Java Audio Video Encoder) library is Java wrapper on the ffmpeg project. Developers can take take advantage of JAVE to transcode audio and video files from a format to another (
    Downloads: 5 This Week
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