Open Source Java Software - Page 30
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Java Software
Browse free open source Java Software and projects below. Use the toggles on the left to filter open source Java Software by OS, license, language, programming language, and project status.
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Aeron
Efficient UDP unicast, UDP multicast, and IPC message transport
Efficient reliable UDP unicast, UDP multicast, and IPC message transport. Java and C++ clients are available in this repository, and a .NET client is available from a 3rd party. All three clients can exchange messages across machines, or on the same machine via IPC, very efficiently. Message streams can be recorded by the Archive module to persistent storage for later, or real-time, replay. Aeron Cluster provides support for fault-tolerant services as replicated state machines based on the Raft consensus algorithm. Performance is the key focus. A design goal for Aeron is to be the highest throughput with the lowest and most predictable latency of any messaging system. Aeron integrates with Simple Binary Encoding (SBE) for the best possible message encoding and decoding performance. Many of the data structures used in the creation of Aeron have been factored out to the Agrona project. -
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Apache Kafka
Mirror of Apache Kafka
Apache Kafka is a distributed streaming platform built around durable, partitioned logs called topics, enabling high-throughput, fault-tolerant event pipelines. Producers append records to partitions, brokers replicate them for durability, and consumer groups read them at their own pace while balancing work across instances. The commit/offset model and retention policies support patterns from real-time processing to event sourcing and audit trails. Exactly-once processing semantics, idempotent producers, and transactions help prevent duplicates across complex dataflows. Kafka Streams and Kafka Connect extend the core: Streams provides a library for stateful stream processing within applications, while Connect standardizes integration with external systems. With horizontal scalability, strong ordering guarantees within partitions, and mature tooling, Kafka serves as the backbone for event-driven architectures across analytics, microservices, and data integration. -
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Arthas
Alibaba Java Diagnostic Tool
Often times, the production system network is inaccessible from the local development environment. If issues are encountered in production systems, it is impossible to use IDEs to debug the application remotely. More importantly, debugging in production environment is unacceptable, as it will suspend all the threads, resulting in the suspension of business services. Developers could always try to reproduce the same issue on the test/staging environment. However, this is tricky as some issues cannot be reproduced easily on a different environment, or even disappear once restarted. And if you're thinking of adding some logs to your code to help troubleshoot the issue, you will have to go through the following lifecycle; test, staging, and then to production. Time is money! This approach is inefficient! Besides, the issue may not be reproducible once the JVM is restarted, as described above. Arthas was built to solve these issues. -
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Axon Framework
Framework for Evolutionary Message-Driven Microservices on the JVM
Axon provides a unified, productive way of developing Java applications that can evolve without significant refactoring from a monolith to Event-Driven microservices. Axon includes both a programming model as well as specialized infrastructure to provide enterprise-ready operational support for the programming model - especially for scaling and distributing mission-critical business applications. Axon is composed of the following concepts and products. Domain-Driven Design (DDD) defines many concepts and patterns that help design software effectively, in line with the business requirements. Axon separates infrastructural concerns from the domain logic, which, combined with DDD best practices, keeps complexity to a minimum. Event Sourcing is a pattern for data storage, where instead of storing the current state of any entity, all past changes to that state are stored. -
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BungeeCord
BungeeCord, the 6th in a generation of server portal suites
BungeeCord is a Minecraft server proxy designed to connect multiple Minecraft servers into one larger network. It lets players move between separate servers while experiencing them as part of the same connected environment. The project is maintained by SpigotMC and has long been used by server owners who operate lobby, minigame, survival, creative, and specialized game-mode networks. BungeeCord works as a layer between players and backend servers, forwarding connections and managing server-to-server transitions. It also provides an API that developers can use to create plugins and extend proxy behavior. Its main value is helping Minecraft communities scale beyond a single server while keeping navigation smoother for players. -
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ChatGPT Java
A Java client for the ChatGPT API
ChatGPT Java is a Java client for the ChatGPT API. Use official API with model gpt-3.5-turbo. -
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Codeboard
Codeboard App
CodeBoard is an open‑source Android keyboard tailored for coding. It consolidates symbols, code navigation, editing shortcuts, and clipboard tools into one keyboard—eliminating constant layout switching between alphabets, numbers, and symbols. -
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Epoxy
Android library for building complex screens in a RecyclerView
Epoxy is an Android library for building complex screens in a RecyclerView. Models are automatically generated from custom views or databinding layouts via annotation processing. These models are then used in an EpoxyController to declare what items to show in the RecyclerView. This abstracts the boilerplate of view holders, diffing items and binding payload changes, item types, item ids, span counts, and more, in order to simplify building screens with multiple view types. Additionally, Epoxy adds support for saving view state and automatic diffing of item changes. We developed Epoxy at Airbnb to simplify the process of working with RecyclerViews, and to add the missing functionality we needed. We now use Epoxy for most of the main screens in our app and it has improved our developer experience greatly. If you are using layout resources in Epoxy annotations then for library projects add Butterknife's gradle plugin to your buildscript. -
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Event Ruler
Java library that allows matching many thousands of Events per second
Event Ruler (called Ruler in the rest of the doc for brevity) is a Java library that allows matching Rules to Events. An event is a list of fields, which may be given as name/value pairs or as a JSON object. A rule associates event field names with lists of possible values. Event Ruler is a Java library that allows matching many thousands of Events per second to any number of expressive and sophisticated rules. -
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GeoServer
GeoServer repository
GeoServer is an open-source software server written in Java that allows users to share and edit geospatial data. Designed for interoperability, it publishes data from any major spatial data source using open standards. Being a community-driven project, GeoServer is developed, tested, and supported by a diverse group of individuals and organizations from around the world. GeoServer is the reference implementation of the Open Geospatial Consortium (OGC) Web Feature Service (WFS) and Web Coverage Service (WCS) standards, as well as a high-performance certified compliant Web Map Service (WMS), compliant Catalog Service for the Web (CSW) and implementing Web Processing Service (WPS). GeoServer forms a core component of the Geospatial Web. -
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Hello Algorithm
Animated illustrations, one-click data structure
Animated illustrations, one-click data structure and algorithm tutorials. This project aims to create an open source, free, novice-friendly introductory tutorial on data structures and algorithms. The whole book uses animated illustrations, the content is clear and easy to understand, and the learning curve is smooth, guiding beginners to explore the knowledge map of data structures and algorithms. The source code can be run with one click, helping readers improve their programming skills during exercises and understand the working principles of algorithms and the underlying implementation of data structures. Readers are encouraged to help each other learn, and questions and comments can usually be answered within two days. -
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IK Analysis for Elasticsearch
A plugin that integrates Lucene IK analyzer into elasticsearch
IK Analyzer is an open source, lightweight Chinese word segmentation toolkit developed based on java language. Since the release of version 1.0 in December 2006, IKAnalyzer has launched 4 major versions. Initially, it was a Chinese word segmentation component based on the open source project Luence as the main application, combined with dictionary word segmentation and grammar analysis algorithms. Starting from version 3.0, IK has developed into a common word segmentation component for Java, independent of the Lucene project, and at the same time provides a default optimized implementation of Lucene. In the 2012 version, IK implemented a simple word segmentation ambiguity elimination algorithm, marking the evolution of the IK tokenizer from pure dictionary word segmentation to analog semantic word segmentation. -
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Iris
A modern shaders mod for Minecraft compatible with existing OptiFine
Iris was created to fill a void that I saw in the Minecraft customization and graphical enhancement community: the lack of an open-source shaders mod that would let me load my favorite shader packs on modern versions of the game, while retaining performance and compatibility with modpacks. OptiFine, the current dominant mod for loading shader packs, has restrictive licensing that firmly stands in the way of any sort of tinkering, and is fairly notorious for having compatibility issues with the mods that I like. It's also mutually incompatible with Sodium, the best rendering optimization mod in existence by a large margin. ShadersMod was never updated past 1.12, and it lacks support for many of the many modern popular shaderpacks. So I created Iris, to try and solve these issues, and also address many other longstanding issues with shader packs. I first and foremost develop Iris to meet my own needs of a performance-oriented shaders mod with good compatibility. -
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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. -
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Jailer Database Tool
Database subsetting and relational data browsing tool
Jailer is a tool for database subsetting, schema and data browsing. It creates small slices from your database and lets you navigate through your database following the relationships. Ideal for creating small samples of test data or for local problem analysis with relevant production data. Creates small slices from your productive database and imports the data into your development and test environment (consistent and referentially intact). Improves database performance by removing and archiving obsolete data without violating integrity. The Data Browser lets you navigate through your database following the relationships (foreign key-based or user-defined) between tables. Generates SQL (topologically sorted), XML (hierarchically structured) and DbUnit datasets. A demo database is included with which you can get a first impression without any configuration effort. -
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JavaCPP
The missing bridge between Java and native C++
JavaCPP provides efficient access to native C++ inside Java, not unlike the way some C/C++ compilers interact with assembly language. No need to invent new languages such as with SWIG, SIP, C++/CLI, Cython, or RPython. Instead, similar to what cppyy strives to do for Python, it exploits the syntactic and semantic similarities between Java and C++. Under the hood, it uses JNI, so it works with all implementations of Java SE, in addition to Android, Avian, and RoboVM (instructions). More specifically, when compared to the approaches above or elsewhere (CableSwig, JNIGeneratorApp, cxxwrap, JNIWrapper, Platform Invoke, GlueGen, LWJGL Generator, JNIDirect, ctypes, JNA, JNIEasy, JniMarshall, JNative, J/Invoke, HawtJNI, JNR, BridJ, CFFI, fficxx, CppSharp, cgo, pybind11, rust-bindgen, Panama Native, etc.), it maps naturally and efficiently many common features afforded by the C++ language and often considered problematic, including overloaded operators, class and function templates, etc. -
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Kestra
Kestra is an infinitely scalable orchestration and scheduling platform
Build reliable workflows, blazingly fast, deploy in just a few clicks. Kestra is an open-source, event-driven orchestrator that simplifies data operations and improves collaboration between engineers and business users. By bringing Infrastructure as Code best practices to data pipelines, Kestra allows you to build reliable workflows and manage them with confidence. Thanks to the declarative YAML interface for defining orchestration logic, everyone who benefits from analytics can participate in the data pipeline creation process. The UI automatically adjusts the YAML definition any time you make changes to a workflow from the UI or via an API call. Therefore, the orchestration logic is defined declaratively in code, even if some workflow components are modified in other ways. -
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Kryo
Java binary serialization and cloning, fast, efficient, automatic
Kryo is a fast and efficient binary object graph serialization framework for Java. The goals of the project are high speed, low size, and an easy-to-use API. The project is useful any time objects need to be persisted, whether to a file, database or over the network. Kryo can also perform automatic deep and shallow copying/cloning. This is direct copying from object to object, not object to bytes to object. Kryo has three sets of methods for reading and writing objects. If the concrete class of the object is not known and the object could be null. Besides methods to read and write objects, the Kryo class provides a way to register serializers, reads and writes class identifiers efficiently, handles null objects for serializers that can't accept nulls, and handles reading and writing object references (if enabled). This allows serializers to focus on their serialization tasks. -
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MeGit
Standalone Git GUI based on EGit
Looking for a powerful, yet easy-to-use, fully open-source user interface for git? Well, there are plenty of options. One of our favorites is EGit. However, EGit is actually a plug-in for Eclipse rather than a standalone tool, such as GitKraken, etc. Nevertheless, even in projects where we actually use other editors or IDEs than Eclipse, we often found ourselves firing up an Eclipse IDE with EGit just to handle more complex git branch operations, for analysing the git history, and so on. This made us think, wouldn't EGit be a great git standalone tool if it would be... well, an actual standalone tool? That's exactly what MeGit is: a minimal standalone application that contains just enough to run EGit conveniently. Nice visualization of the git history making it easy to keep a good overview when analyzing, merging or rebasing branches, cherry-picking commits, changing the git history, etc. -
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Mixin
Mixin is a trait/mixin and bytecode weaving framework for Java
Mixin is a trait/mixin framework for Java using ASM and hooking into the runtime classloading process via a set of pluggable built-in or user-provided services. Built-in services currently support Mojang's LegacyLauncher system, though this is deprecated in favor of ModLauncher by cpw, which has greater extensibility and has support for Java 8 and later. Additional documentation for individual features and annotations can be found in the extensive Javadoc. For additional help use the channel #mixin on the Sponge Discord Server. For handling obfuscation tasks, Mixin provides an Annotation Processor which works at compile time to generate obfuscation mappings for your toolchain to apply. If using Gradle 5 or later, annotation processors are no longer automatically loaded from compile configurations and must be specified explicitly via annotationProcessor configurations. -
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Mockito
Most popular Mocking framework for unit tests written in Java
Mockito downloads and instructions for setting up Maven, Gradle and other build systems are available from the Central Repository and Bintray. Mockito 3.x requires Java 8, but otherwise doesn’t introduce any breaking changes compared to the 2.x series. Mockito 2.25.0 had an important feature added for anyone using mockito-inline. In particular anyone using Kotlin (which demands using mockito-inline) and PowerMock (which exacerbates the problem even more) will want to add this to all of their test classes to avoid a large memory leak. Fancy getting world-wide visibility and building up an eternal fame of an OSS contributor? Use the latest version! Hack and experiment. Speak up at the mailing list. Mockito is a mocking framework that tastes really good. It lets you write beautiful tests with a clean & simple API. Mockito doesn’t give you hangover because the tests are very readable and they produce clean verification errors. -
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MusicDNA
Experience your favorite music in a unique way
MusicDNA is a music player unlike any other. It is an Android music player that renders beautiful DNA (visualization) of the currently playing music. It does this through the use of the Visualizer Class, and is inspired by paullewis's music-dna. It uses the FFT Data supplied by the Visualizer class of Android , calculating the Amplitude at that exact moment and using this to plot the DNA. MusicDNA fuses the functionality of traditional music players with stunning visualizations. In this way it captivates not only the sense of hearing but the sense of sight as well. MusicDNA's player allows for playing both local music as well as streamed music from SoundCloud. -
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Nextcloud Android app
The Android client for Nextcloud
Nextcloud Android app is the Android client for Nextcloud, a private file sync & share and communication server. It lets you access all of your files easily on your Nextcloud from any Android device. Nextcloud Android app is easy to use and completely open source, so you can host it yourself or have a company do it for you. Always stay in control of your photos, calendar, contact data and other documents and files with Nextcloud. -
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OpenAudible
Audiobook Manager for Audible Users
OpenAudible is a cross-platform audiobook manager designed for Audible users. Manage/Download all your audiobooks with this easy-to-use desktop application. Say goodbye to the hassle of managing your audiobooks across multiple devices. With OpenAudible, you can easily download, view, and manage all your Audible books in one place. Our lightning-fast conversion to MP3 and M4B audio formats makes it easy to enjoy your favorite books on any device. Plus, our automation features make it a breeze to update your library after buying new books. Don't just take our word for it - see what our satisfied users say. Get started with OpenAudible today and experience the ultimate audiobook management solution. -
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OpenDataLoader PDF
PDF Parser for AI-ready data. Automate PDF accessibility
OpenDataLoader PDF is an open-source document processing system designed to convert complex PDF files into structured, AI-ready formats such as Markdown, JSON, and HTML while preserving layout, hierarchy, and semantic meaning. It focuses on enabling downstream use cases like retrieval-augmented generation (RAG), knowledge extraction, and document intelligence pipelines by maintaining accurate reading order and spatial metadata through bounding boxes. The tool combines deterministic parsing methods with an optional hybrid AI-powered mode that improves extraction quality for difficult layouts such as multi-column documents, scanned files, and scientific papers. It includes built-in OCR capabilities supporting dozens of languages, making it suitable for digitizing low-quality or image-based PDFs. A key differentiator is its emphasis on accessibility automation, as it can generate tagged PDFs aligned with accessibility standards, significantly reducing manual remediation effort.
