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.

  • Forever Free Full-Stack Observability | Grafana Cloud Icon
    Forever Free Full-Stack Observability | Grafana Cloud

    Our generous forever free tier includes the full platform, including the AI Assistant, for 3 users with 10k metrics, 50GB logs, and 50GB traces.

    Built on open standards like Prometheus and OpenTelemetry, Grafana Cloud includes Kubernetes Monitoring, Application Observability, Incident Response, plus the AI-powered Grafana Assistant. Get started with our generous free tier today.
    Create free account
  • MongoDB Atlas runs apps anywhere Icon
    MongoDB Atlas runs apps anywhere

    Deploy in 115+ regions with the modern database for every enterprise.

    MongoDB Atlas gives you the freedom to build and run modern applications anywhere—across AWS, Azure, and Google Cloud. With global availability in over 115 regions, Atlas lets you deploy close to your users, meet compliance needs, and scale with confidence across any geography.
    Start Free
  • 1
    libjpeg-turbo

    libjpeg-turbo

    SIMD-accelerated libjpeg-compatible JPEG codec library

    libjpeg-turbo is a JPEG image codec that uses SIMD instructions (MMX, SSE2, NEON, AltiVec) to accelerate baseline JPEG compression and decompression on x86, x86-64, ARM, and PowerPC systems. On such systems, libjpeg-turbo is generally 2-6x as fast as libjpeg, all else being equal. On other types of systems, libjpeg-turbo can still outperform libjpeg by a significant amount, by virtue of its highly-optimized Huffman coding routines. In many cases, the performance of libjpeg-turbo rivals that of proprietary high-speed JPEG codecs. libjpeg-turbo implements both the traditional libjpeg API as well as the less powerful but more straightforward TurboJPEG API. libjpeg-turbo also features colorspace extensions that allow it to compress from/decompress to 32-bit and big-endian pixel buffers (RGBX, XBGR, etc.), as well as a full-featured Java interface.
    Leader badge
    Downloads: 42,549 This Week
    Last Update:
    See Project
  • 2
    Recaf

    Recaf

    The modern Java bytecode editor

    Recaf is an open-source Java bytecode editor that simplifies the process of editing compiled Java applications. To make things easier Recaf abstracts away much of the internal class file format. Difficult tasks such as updating stack-frames are done automatically. Along with additional features to assist in the process of editing classes, Recaf is the most feature-rich free bytecode editor available. While Recaf makes bytecode editing a more simple process it does not mean you should dive head-first into editing compiled Java applications without understanding some basic programming concepts and the Java class file architecture.
    Downloads: 281 This Week
    Last Update:
    See Project
  • 3
    Hacker Scripts

    Hacker Scripts

    Based on a true story

    Hacker Scripts is a cheeky collection of small automation scripts and language ports collected under the tagline “Based on a true story.” The repository gathers playful utilities (originally shell and Ruby scripts) that automate short, real-world tasks — for example, sending a quick “late at work” text when SSH sessions are active, firing off an automated “I’m sick / working from home” email on certain mornings, or even talking to a networked coffee machine to start brewing at precisely the right moment. The README explains the origin story and highlights several canonical scripts and provides usage notes such as required environment variables and cron examples for scheduling. Contributors have provided implementations and ports in many languages and folders (shell, Ruby, Python, Node, Perl, PowerShell, Go, Java, etc.), and the project explicitly welcomes pull requests that add additional language implementations.
    Downloads: 166 This Week
    Last Update:
    See Project
  • 4
    UCanAccess

    UCanAccess

    A pure Java JDBC driver for Microsoft Access database files

    UCanAccess is a pure Java JDBC Driver implementation which allows Java developers and JDBC client programs to read/write Microsoft Access database (.mdb and .accdb) files. No ODBC needed.
    Leader badge
    Downloads: 699 This Week
    Last Update:
    See Project
  • AI-generated apps that pass security review Icon
    AI-generated apps that pass security review

    Stop waiting on engineering. Build production-ready internal tools with AI—on your company data, in your cloud.

    Retool lets you generate dashboards, admin panels, and workflows directly on your data. Type something like “Build me a revenue dashboard on my Stripe data” and get a working app with security, permissions, and compliance built in from day one. Whether on our cloud or self-hosted, create the internal software your team needs without compromising enterprise standards or control.
    Try Retool free
  • 5
    JSON-java

    JSON-java

    A reference implementation of a JSON package in Java

    JSON is a light-weight language-independent data interchange format. The JSON-Java package is a reference implementation that demonstrates how to parse JSON documents into Java objects and how to generate new JSON documents from the Java classes.
    Downloads: 94 This Week
    Last Update:
    See Project
  • 6
    JFreeChart
    JFreeChart is a free (LGPL) chart library for the Java(tm) platform. It supports bar charts, pie charts, line charts, time series charts, scatter plots, histograms, simple Gantt charts, Pareto charts, bubble plots, dials, thermometers and more. *** JFreeChart has moved to GitHub: https://github.com/jfree/jfreechart ***
    Leader badge
    Downloads: 413 This Week
    Last Update:
    See Project
  • 7
    Autopsy

    Autopsy

    Autopsy® is a digital forensics platform and graphical interface

    Autopsy® is a digital forensics platform and graphical interface to The Sleuth Kit® and other digital forensics tools. It can be used by law enforcement, military, and corporate examiners to investigate what happened on a computer. You can even use it to recover photos from your camera's memory card. Autopsy was designed to be intuitive out of the box. Installation is easy and wizards guide you through every step. All results are found in a single tree. See the intuitive page for more details. Autopsy was designed to be an end-to-end platform with modules that come with it out of the box and others that are available from third-parties.
    Downloads: 84 This Week
    Last Update:
    See Project
  • 8
    Aliucord

    Aliucord

    A modification for the Discord Android App

    Aliucord is a modification for the Android Discord app.
    Downloads: 79 This Week
    Last Update:
    See Project
  • 9
    ZXing

    ZXing

    Barcode scanning library for Java, Android

    ZXing or “Zebra Crossing” is an open source multi-format 1D/2D barcode image processing library that’s been implemented in Java, and also comes with ports to other languages. It currently supports the following formats: UPC-A and UPC-E EAN-8 and EAN-13 Code 39 Code 93 Code 128 ITF Codabar RSS-14 (all variants) RSS Expanded (most variants) QR Code Data Matrix Aztec ('beta' quality) PDF 417 ('alpha' quality) MaxiCode ZXing is made up of several modules, including a core image decoding library, JavaSE-specific client code, and Android client Barcode Scanner. It is the basis of many other third-party open source projects.
    Downloads: 68 This Week
    Last Update:
    See Project
  • Earn up to 16% annual interest with Nexo. Icon
    Earn up to 16% annual interest with Nexo.

    Access competitive interest rates on your digital assets.

    Generate interest, borrow against your crypto, and trade a range of cryptocurrencies — all in one platform. Geographic restrictions, eligibility, and terms apply.
    Get started with Nexo.
  • 10
    EssentialsX

    EssentialsX

    The modern Essentials suite for Spigot and Paper

    EssentialsX is a continuation of the Essentials plugin suite, updated to support modern Minecraft and Spigot versions. It provides countless new features, performance enhancements and fixes that are not available in the original Essentials or Spigot-Essentials. If you're coming from the original Essentials plugin, EssentialsX is a drop-in replacement for Essentials.
    Downloads: 56 This Week
    Last Update:
    See Project
  • 11
    EMV NFC Paycard Enrollment

    EMV NFC Paycard Enrollment

    A Java library used to read and extract data from NFC EMV credit cards

    Java library used to read and extract public data from NFC EMV credit cards.
    Downloads: 39 This Week
    Last Update:
    See Project
  • 12
    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: 28 This Week
    Last Update:
    See Project
  • 13
    iText

    iText

    iText for Java represents the next level of SDKs for developers

    iText for Java represents the next level of SDKs for developers who want to take advantage of the benefits PDF can bring. Equipped with a better document engine, high and low-level programming capabilities and the ability to create, edit, and enhance PDF documents, iText can be a boon to nearly every workflow. iText Suite refers to the complete line of products comprising the open-source iText Core PDF library and its add-ons. The iText Suite is a fully-featured SDK for PDF development that allows you to seamlessly embed extensive PDF functionality into your software or workflows. The iText Suite builds on over a decade of lessons learned from iText 5 (and iTextSharp) development. The latest release of iText, version 8, is a simpler, more performant and extensible library that is ready to handle the increased challenges of today's document workflows, one add-on at a time.
    Downloads: 24 This Week
    Last Update:
    See Project
  • 14
    LWJGL

    LWJGL

    Java library that enables cross-platform access to popular native APIs

    LWJGL is a Java library that enables cross-platform access to popular native APIs useful in the development of graphics (OpenGL, Vulkan), audio (OpenAL) and parallel computing (OpenCL) applications. This access is direct and high-performance, yet also wrapped in a type-safe and user-friendly layer, appropriate for the Java ecosystem. LWJGL is an enabling technology and provides low-level access. It is not a framework and does not provide higher-level utilities than what the native libraries expose. As such, novice programmers are encouraged to try one of the frameworks or game engines that make use of LWJGL, before working directly with the library.
    Downloads: 21 This Week
    Last Update:
    See Project
  • 15
    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: 19 This Week
    Last Update:
    See Project
  • 16
    Spoon

    Spoon

    Metaprogramming library to analyze and transform Java source code

    Spoon is an open-source library to analyze, rewrite, transform, transpile Java source code. It parses source files to build a well-designed AST with powerful analysis and transformation API. It supports modern Java versions up to Java 20. Spoon is an official Inria open-source project, and member of the OW2 open-source consortium.
    Downloads: 19 This Week
    Last Update:
    See Project
  • 17
    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: 17 This Week
    Last Update:
    See Project
  • 18
    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: 15 This Week
    Last Update:
    See Project
  • 19
    ConnectBot

    ConnectBot

    ConnectBot is the first SSH client for Android

    ConnectBot is a secure shell client for the Android platform. Its ultimate goal is to create a secure connection through which you can use a shell on a remote machine and transfer files back and forth to your phone. ConnectBot is a powerful open source SSH (Secure Shell) client. It can handle several simultaneous sessions, create secure connections in tunnel mode and allows Copy/Paste from other applications. This client allows you to connect to SSH (Secure Shell) servers that typically include UNIX-based servers.
    Downloads: 11 This Week
    Last Update:
    See Project
  • 20
    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: 11 This Week
    Last Update:
    See Project
  • 21
    VisualVM

    VisualVM

    VisualVM is an All-in-One Java Troubleshooting Tool

    VisualVM is a visual tool integrating command line JDK tools and lightweight profiling capabilities. Designed for both development and production time use. Use Apache Ant 1.9.9 or above and Oracle JDK 8 to build VisualVM from this repository. VisualVM monitors and troubleshoots applications running on Java 1.4+ from many vendors using various technologies including jvmstat, JMX, Serviceability Agent (SA) and Attach API. VisualVM perfectly fits all the requirements of application developers, system administrators, quality engineers and end users. VisualVM automatically detects and lists locally and remotely running Java applications (jstatd must be running on the remote host). You can also define applications manually by JMX connection. For each process VisualVM shows basic runtime information: PID, main class, arguments passed to java process, JVM version, JDK home, JVM flags and arguments and System properties.
    Downloads: 11 This Week
    Last Update:
    See Project
  • 22
    A Java JNA wrapper for Tesseract OCR API
    Leader badge
    Downloads: 67 This Week
    Last Update:
    See Project
  • 23
    JTS Topology Suite

    JTS Topology Suite

    Java library for creating and manipulating vector geometry.

    The JTS Topology Suite is a Java library for creating and manipulating vector geometry. It also provides a comprehensive set of geometry test cases, and the TestBuilder GUI application for working with and visualizing geometry and JTS functions.
    Downloads: 10 This Week
    Last Update:
    See Project
  • 24
    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: 9 This Week
    Last Update:
    See Project
  • 25
    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
    Last Update:
    See Project
  • Previous
  • You're on page 1
  • 2
  • 3
  • 4
  • 5
  • Next
MongoDB Logo MongoDB