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.

  • Data management solutions for confident marketing Icon
    Data management solutions for confident marketing

    For companies wanting a complete Data Management solution that is native to Salesforce

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  • Award-Winning Medical Office Software Designed for Your Specialty Icon
    Award-Winning Medical Office Software Designed for Your Specialty

    Succeed and scale your practice with cloud-based, data-backed, AI-powered healthcare software.

    RXNT is an ambulatory healthcare technology pioneer that empowers medical practices and healthcare organizations to succeed and scale through innovative, data-backed, AI-powered software.
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  • 1
    EasyExcel

    EasyExcel

    Lightweight Java library developed by Alibaba for reading and writing

    EasyExcel is a Java library focused on reading and writing Excel files with very low memory usage, making it suitable for large datasets that overwhelm traditional APIs. It uses streaming/event-driven parsing to avoid loading entire workbooks into memory, and it maps rows to Java objects via simple annotations. Writers support multiple sheets, custom styles, merged cells, and template-based filling so production reports remain maintainable. The API emphasizes developer ergonomics: callbacks are straightforward, converters handle common type transformations, and header/column mapping is explicit. It integrates cleanly into Spring/enterprise stacks, often as part of import/export pipelines or scheduled report generation. By optimizing both performance and ease of use, EasyExcel reduces operational risk around big Excel jobs in web services and back-office tools.
    Downloads: 15 This Week
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  • 2
    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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  • 3
    jclasslib bytecode editor

    jclasslib bytecode editor

    Visualizes all aspects of compiled Java class files

    jclasslib bytecode editor is a tool that visualizes all aspects of compiled Java class files and the contained bytecode. Many aspects of class files can be edited in the UI. In addition, it contains a library that enables developers to read and write Java class files and bytecode. All constant pool entries can be edited. Referenced constant pool entries can directly be edited from the context menu that is shown by the "Edit" button of attributes and constant pool entries. Bytecode instructions can be edited from the context menu.
    Downloads: 15 This Week
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  • 4
    Alibaba Dragonwell8

    Alibaba Dragonwell8

    Alibaba Dragonwell8 JDK

    Over the years, more than a billion lines of Java code have been written in Alibaba. While adopting OpenJDK to run these applications, we have found a need to customize it specifically for large-scale Java application deployments. Our customization has been well-tested in our environment. We are now contributing some of our work into the Java community. Alibaba Dragonwell, as a downstream version of OpenJDK, is the in-house OpenJDK implementation at Alibaba. It is optimized for online e-commerce, financial and logistics applications running on 100,000+ servers. Alibaba Dragonwell is the engine that runs these distributed Java applications in extreme scaling.
    Downloads: 14 This Week
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  • Field Sales+ for MS Dynamics 365 and Salesforce Icon
    Field Sales+ for MS Dynamics 365 and Salesforce

    Maximize your sales performance on the go.

    Bring Dynamics 365 and Salesforce wherever you go with Resco’s solution. With powerful offline features and reliable data syncing, your team can access CRM data on mobile devices anytime, anywhere. This saves time, cuts errors, and speeds up customer visits.
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  • 5
    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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  • 6
    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: 14 This Week
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  • 7
    AWS Secrets Manager JDBC Library

    AWS Secrets Manager JDBC Library

    The AWS Secrets Manager JDBC Library for Java developers

    The AWS Secrets Manager JDBC Library enables Java developers to easily connect to SQL databases using secrets stored in AWS Secrets Manager. We provide database drivers that intercept calls to real database drivers and swap out secret IDs for actual login credentials. This prevents hard-coding database credentials into your application code. This can be integrated into your app through a few configuration file changes. Change the jdbc url to one that our driver will intercept (starting with jdbc-secretsmanager), Change the c3p0 user to be the secret ID of the secret in secrets manager that has the username and password, and change the driverClass to be our driver wrapper. The secret being used should be in the JSON format we use for our rotation lambdas for RDS databases.
    Downloads: 13 This Week
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  • 8
    AnLinux

    AnLinux

    AnLinux allow you to run Linux on Android without root access

    AnLinux allow you to run Linux on Android without root access. The bash script downloads the image over the internet, then decompresses the image, and then mounts it using PRoot.
    Downloads: 13 This Week
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  • 9
    JMX Exporter

    JMX Exporter

    A process for exposing JMX Beans via HTTP for Prometheus consumption

    JMX to Prometheus exporter: a collector that can configurable scrape and expose mBeans of a JMX target. This exporter is intended to be run as a Java Agent, exposing a HTTP server and serving metrics of the local JVM. It can be also run as a standalone HTTP server and scrape remote JMX targets, but this has various disadvantages, such as being harder to configure and being unable to expose process metrics (e.g., memory and CPU usage). Running the exporter as a Java agent is strongly encouraged.
    Downloads: 13 This Week
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  • 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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  • 10
    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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  • 11
    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: 12 This Week
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  • 12
    A Java JNA wrapper for Tesseract OCR API
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    Downloads: 75 This Week
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  • 13
    AtlantaFX

    AtlantaFX

    Modern JavaFX CSS theme collection with additional controls

    Modern JavaFX CSS theme collection with additional controls.
    Downloads: 11 This Week
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  • 14
    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: 11 This Week
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  • 15
    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: 11 This Week
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  • 16
    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: 10 This Week
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  • 17
    HikariCP

    HikariCP

    A solid, high-performance, JDBC connection pool at last

    HikariCP is a high-performance JDBC connection pooling library designed to offer minimal overhead and maximum throughput. It aims for simplicity and stability, concentrating on fast connection acquisition and minimal latency under load. Its internals manage a pool of connections aggressively but smartly, with options such as leak detection, timeout thresholds, and adaptive connection retirement. Because it avoids heavy internal locking, it scales well in high-concurrency environments, making it a popular choice in microservices and high-throughput web backends. Metrics and instrumentation hooks (for example, via Dropwizard or Micrometer) allow runtime visibility into pool usage and health. HikariCP’s focus is on doing the essential work of pooling correctly and efficiently, rather than bundling extraneous features.
    Downloads: 10 This Week
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  • 18
    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: 10 This Week
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  • 19
    Prometheus JVM Client

    Prometheus JVM Client

    Prometheus instrumentation library for JVM applications

    It supports Java, Clojure, Scala, JRuby, and anything else that runs on the JVM. If you use Maven, you can simply reference the assets below. The latest version can be found on in the maven repository for io.prometheus. By default, counters, histograms, and summaries export an additional series suffixed with _created and a value of the unix timestamp for when the metric was created. Building the repository needs Java 11 (The project the project still supports Java 6 and Java versions > 11 dropped support for Java 6 output). We recommend to use an up-to-data Java 8 installation. The project provides the maven wrapper and therefore no local maven installation is needed. To build the repository just call ./mvnw verify.
    Downloads: 10 This Week
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  • 20
    Spring Integration

    Spring Integration

    Provides an extension of the Spring programming model

    Extends the Spring programming model to support the well-known Enterprise Integration Patterns. Spring Integration enables lightweight messaging within Spring-based applications and supports integration with external systems via declarative adapters. Those adapters provide a higher-level of abstraction over Spring’s support for remoting, messaging, and scheduling. Spring Integration’s primary goal is to provide a simple model for building enterprise integration solutions while maintaining the separation of concerns that is essential for producing maintainable, testable code.
    Downloads: 10 This Week
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  • 21
    Hutool

    Hutool

    A set of tools that keep Java sweet

    Hutool is a small but comprehensive Java tool class library. Through static method encapsulation, it reduces the learning cost of related APIs, improves work efficiency, makes Java as elegant as a functional language, and makes the Java language "sweet". The tools and methods in Hutool come from each user's meticulous attention to detail. It covers all aspects of the underlying code of Java development. It is not only a sharp tool to solve small problems in large-scale project development, but also an efficiency responsibility in small-scale projects. Hutool is a friendly replacement for the "util" package in the project. It saves developers the time of encapsulating public classes and public tool methods in the project, allowing developers to focus on business while avoiding bugs caused by imperfect encapsulation to the greatest extent.
    Downloads: 9 This Week
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  • 22
    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: 9 This Week
    Last Update:
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  • 23
    Logbook

    Logbook

    An extensible Java library for HTTP request and response logging

    Logbook is an extensible Java library to enable complete request and response logging for different client- and server-side technologies. It satisfies a special need by a) allowing web application developers to log any HTTP traffic that an application receives or sends b) in a way that makes it easy to persist and analyze it later. This can be useful for traditional log analysis, meeting audit requirements or investigating individual historic traffic issues. Logbook is ready to use out of the box for most common setups. Even for uncommon applications and technologies, it should be simple to implement the necessary interfaces to connect a library/framework/etc. to it.
    Downloads: 9 This Week
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  • 24
    OpenAPI Generator

    OpenAPI Generator

    OpenAPI Generator allows generation of API client libraries

    With 50+ client generators, you can easily generate code to interact with any server which exposes an OpenAPI document. Maintainers of APIs may also automatically generate and distribute clients as part of official SDKs. Each client supports different options and features, but all templates can be replaced with your own Mustache-based templates. Getting started with server development can be tough, especially if you're evaluating technologies. We can reduce the burden when you bring your own OpenAPI document. Some generators support Inversion of Control, allowing you to iterate on design via your OpenAPI document without worrying about blowing away your entire domain layer when you regenerate code. Ever wanted to iteratively design a MySQL database, but writing table declarations was too tedious? OpenAPI documents allow you to convert the metadata about your API into some other format.
    Downloads: 9 This Week
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  • 25
    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: 9 This Week
    Last Update:
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