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
    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: 8 This Week
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  • 2
    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: 8 This Week
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  • 3
    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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  • 4
    Kamon Telemetry

    Kamon Telemetry

    Distributed Tracing, Metrics and Context Propagation for applications

    Kamon Telemetry is a set of libraries for instrumenting applications running on the JVM. With Kamon Telemetry you can collect metrics, propagate context across threads and services, and get distributed traces automatically. The best way to get started is by following our installation guides and taking it from there. Have fun with Kamon. Monitor your backend applications, fix performance issues, and get alerted when problems happen. All without being a monitoring expert. Everybody starts monitoring with logs because they are there by default. Just connect to your server and start tailing. But logs have a hard time showing you the overall response times for your application, or whether certain calls to the database are happening in sequence or parallel (among a million other things).
    Downloads: 8 This Week
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  • 5
    Louvre

    Louvre

    A small customizable library useful to handle an image gallery

    A small customizable image picker. Useful to handle a gallery image pick action built-in your app.
    Downloads: 8 This Week
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  • 6
    MPAndroidChart

    MPAndroidChart

    A powerful Android chart view / graph view library

    MPAndroidChart is a powerful chart library for Android that offers a beautiful and comprehensive range of charts and graphs. Powerful and very easy to use, it supports the creation of bar-, line-, pie-, bubble-, scatter-, radar- and candlestick charts, as well as scaling, dragging and animations. Charts are rendered cleanly and are visually engaging. Visualizing your data exactly how you want is so much easier with MPAndroidChart. To see more great examples of MPAndroidChart, download the MPAndroidChart Example App on Google Play.
    Downloads: 8 This Week
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  • 7
    Svix

    Svix

    The enterprise-ready webhooks service

    Build a secure, reliable, and scalable webhook platform in minutes using the Svix webhook service. Webhooks require a lot more engineering time, resources and ongoing maintenance than you would first expect. Building a secure, reliable, and scalable webhook service is hard and time-consuming. We built it so you can focus on what matters most, your business. Customer endpoints fail or hang more often than you think. You need automatic retries to ensure deliverability. You need to monitor the deliverability of your webhooks to different endpoints, disable failing ones and notify your customers. Webhooks come with a myriad of security implications, such as SSRF, replay attacks and unauthenticated webhook events. You would need to build a UI for your users to add and remove endpoints, inspect logs and get ongoing reports. Offer your users a great developer experience, including the ability to test, inspect and replay their webhooks.
    Downloads: 8 This Week
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  • 8
    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: 8 This Week
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  • 9
    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
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  • 10
    Helidon

    Helidon

    Java libraries for writing microservices

    Helidon is a cloud-native, open‑source set of Java libraries for writing microservices that run on a fast web core powered by Netty. Helidon Níma is the first Java microservices framework based on virtual threads. Helidon is designed to be simple to use, with tooling and examples to get you going quickly. Since Helidon is simply a collection of Java libraries running on a fast Netty core, there is no extra overhead or bloat. Helidon supports MicroProfile and provides familiar APIs like JAX-RS, CDI and JSON-P/B. Our implementation runs on our fast Helidon Reactive WebServer. Helidon Reactive WebServer provides a modern functional programming model and runs on top of Netty. Lightweight, flexible and reactive, the Helidon WebServer provides a simple-to-use and fast foundation for your microservices.
    Downloads: 7 This Week
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  • 11
    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: 7 This Week
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  • 12
    Javassist

    Javassist

    Java bytecode engineering toolkit

    Javassist (JAVA programming ASSISTant) makes Java bytecode manipulation simple. It is a class library for editing bytecodes in Java; it enables Java programs to define a new class at runtime and to modify a class file when the JVM loads it. Unlike other similar bytecode editors, Javassist provides two levels of API: source level and bytecode level. If the users use the source- level API, they can edit a class file without knowledge of the specifications of the Java bytecode. The whole API is designed with only the vocabulary of the Java language. You can even specify inserted bytecode in the form of source text; Javassist compiles it on the fly. On the other hand, the bytecode-level API allows the users to directly edit a class file as other editors.
    Downloads: 7 This Week
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  • 13
    MyBatis integration with Spring Boot

    MyBatis integration with Spring Boot

    MyBatis integration with Spring Boot

    MyBatis Spring-Boot-Starter will help you to use MyBatis with Spring Boot.
    Downloads: 7 This Week
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  • 14
    Spring Cloud Sleuth

    Spring Cloud Sleuth

    Distributed tracing for spring cloud

    Spring Cloud Sleuth provides Spring Boot auto-configuration for distributed tracing. Sleuth configures everything you need to get started. This includes where trace data (spans) are reported to, how many traces to keep (sampling), if remote fields (baggage) are sent, and which libraries are traced. Add Spring Cloud Sleuth to the classpath of a Spring Boot application (together with a Tracer implementation) and you will see trace IDs in logs.
    Downloads: 7 This Week
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  • 15
    Testcontainers Java

    Testcontainers Java

    Testcontainers is a Java library that supports JUnit tests

    Testcontainers for Java is a Java library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container. Use a containerized instance of a MySQL, PostgreSQL or Oracle database to test your data access layer code for complete compatibility, but without requiring complex setup on developers' machines and safe in the knowledge that your tests will always start with a known DB state. Any other database type that can be containerized can also be used. For running your application in a short-lived test mode with dependencies, such as databases, message queues or web servers. Use containerized web browsers, compatible with Selenium, for conducting automated UI tests. Each test can get a fresh instance of the browser, with no browser state, plugin variations or automated browser upgrades to worry about. And you get a video recording of each test session.
    Downloads: 7 This Week
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  • 16
    Vavr

    Vavr

    Object-functional library that runs with Java 8+

    Vavr core is a functional library for Java. It helps to reduce the amount of code and to increase the robustness. A first step towards functional programming is to start thinking in immutable values. Vavr provides immutable collections and the necessary functions and control structures to operate on these values. The results are beautiful and just work. The Vavr binaries can be found on Maven Central. Beside with Gradle and Maven they work also standalone. The documentation gives an overview and covers the concepts in depth. It is the best way to get started with Vavr. Vavr is open source and can be found on Github. It is distributed under the Apache 2.0 License. There are several additional modules that group around Vavr's core. All of these are supported by the Vavr open-source organization. Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners.
    Downloads: 7 This Week
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  • 17
    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: 7 This Week
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  • 18
    A Java JNA wrapper for Tesseract OCR API
    Downloads: 44 This Week
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  • 19
    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: 6 This Week
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  • 20
    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: 6 This Week
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  • 21
    AtlantaFX

    AtlantaFX

    Modern JavaFX CSS theme collection with additional controls

    Modern JavaFX CSS theme collection with additional controls.
    Downloads: 6 This Week
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  • 22
    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: 6 This Week
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  • 23
    JVM Sandbox

    JVM Sandbox

    Real-time non-invasive AOP framework container based on JVM

    JVM sandbox container, a JVM non-invasive runtime AOP solution. Real-time non-invasive AOP framework container based on JVM. Dynamically enhance the class you specify, get the parameters and line information you want, and even change the method execution. JVM-SANDBOX (sandbox) implements an AOP solution that does not restart or invade the target JVM application. Static knitting occurs when the bytecode is generated, and the AOP bytecode is inserted into the target class and method in advance according to the rules of a certain framework to realize AOP. Dynamic knitting allows the AOP bytecode enhancement of the specified method to be completed during the JVM operation. Most common dynamic knitting schemes use renaming the original method, and then create a new method with the same signature to do the proxy work mode to complete The function of AOP (common implementation scheme such as CgLib), but there are some application boundaries in this way.
    Downloads: 6 This Week
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  • 24

    Material Components for Android

    Modular and customizable Material Design UI components for Android

    Material Components for Android delivers Material Design’s popular and reliable design and development resources to Android developers. With Material Design’s modular and customizable UI components, Android developers can create beautiful, high quality products faster and easier. Developed by a core team of engineers and UX designers at Google, Material Components enable developers to achieve a more reliable development workflow for building exceptional and highly functional apps. Material Components for Android is a drop-in replacement for Android's Design Support Library, offering tried and trusted Material Design guidelines and components.
    Downloads: 6 This Week
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  • 25
    Perl5 plugins for IntelliJ IDEA

    Perl5 plugins for IntelliJ IDEA

    Perl5 plugins for IntelliJ IDEA

    Perl5-IDEA is a plugin for JetBrains IDEs, including IntelliJ IDEA, that provides comprehensive support for Perl 5 development. It enhances the development experience with features like syntax highlighting, code completion, and debugging tools.​
    Downloads: 6 This Week
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