Open Source Java Libraries
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Java Libraries
View 74 business solutionsBrowse 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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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. -
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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. -
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Ollama4j
A simple Java library for interacting with Ollama server
Ollama4j is a lightweight Java library designed to simplify interaction with the Ollama server, enabling developers to integrate locally hosted large language models into Java applications with minimal friction. It provides a clean and developer-friendly API that abstracts the underlying REST communication, allowing users to focus on building features rather than handling low-level networking details. The library supports a wide range of core capabilities, including chat-based interactions, text generation, embeddings, and model management, making it suitable for both simple applications and more advanced AI-driven systems. It integrates seamlessly into Java ecosystems through Maven or Gradle dependencies, and it works with standard Java environments starting from JDK 11 and above. Ollama4j also includes support for advanced features such as tool or function calling, enabling models to interact with external systems and execute more complex workflows. -
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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. -
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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. -
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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. -
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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 ***
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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. -
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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. -
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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. -
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Aliucord
A modification for the Discord Android App
Aliucord is a modification for the Android Discord app. -
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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. -
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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. -
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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. -
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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. -
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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. -
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ta4j
A Java library for technical analysis
Ta4j is an open-source Java library for technical analysis. It provides the basic components for the creation, evaluation, and execution of trading strategies. Ta4j is available on Maven Central. You can also download example code from the maven central repository. The wiki is the best place to start learning about ta4j. For more detailed questions, please use the issues tracker. We can calculate indicators over this bar series, in order to forecast the direction of prices through the study of past market data. Then we have to build our trading strategy. It is made of two trading rules, one for entry, the other for exit. Ta4j comes with a set of basic trading rules/strategies which can be combined using boolean operators. Trading strategies can be easily compared according to a set of analysis criteria. Ta4j can also be used for live trading with more complicated strategies. -
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JFlex
The fast scanner generator for Java™ with full Unicode support
JFlex is a lexical analyzer generator for Java, designed to create fast and efficient scanners. It takes regular expression specifications and produces Java code for tokenizing input text. -
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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. -
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MCProtocolLib
A library for communication with a Minecraft client/server
MCProtocolLib is a simple library for communicating with Minecraft clients and servers. It allows developers to build custom bots, clients, or servers for Minecraft with ease. -
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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. -
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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. -
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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. -
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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. -
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