Open Source Java Software - Page 18
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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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Subsonic is a web-based media streamer, providing ubiquitous access to your music and video collection. More than 20 apps are available for Android, iPhone, Windows Phone, BlackBerry, Roku, Chumby, Sonos etc. Supports virtually all media formats, converting files on the fly. Also includes a Podcast receiver and jukebox feature allowing you to control what's playing on your computer from your mobile phone.
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Web Security Dojo
Virtual training environment to learn web app ethical hacking.
Web Security Dojo is a virtual machine that provides the tools, targets, and documentation to learn and practice web application security testing. A preconfigured, stand-alone training environment ideal for classroom and conferences. No Internet required to use. Ideal for those interested in getting hands-on practice for ethical hacking, penetration testing, bug bounties, and capture the flag (CTF). A single OVA file will import into VirtualBox and VMware. There is also an Ansible script for those brave souls that want transform their stock Ubuntu into a virtual dojo. Bow to your sensei! username: dojo password: dojo -
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Eclipse SQL Client for database querying/browsing any JDBC compliant database. It supports plugins with specialized functionality for individual databases (Oracle, DB2, MySQL, PostgreSQL, Sybase, Informix) and can be extended.
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Impact is an explicit Finite Element Program Suite which simulates dynamic impact events. It has a range of elements, contact handling and different material laws. Models can be created, solved and analyzed with the included pre- and postprocessor. Impact is based on an Explicit Time stepping algorithm. These kind of codes are used to simulate dynamic phenomena such as car crashes and similar, usually involving large deformations.
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SBLIM (pronounced "sublime"), the Standards Based Linux Instrumentation for Manageability is an IBM-initiated Open Source project, intended to enhance the manageability of GNU/Linux systems. It does so by enabling WBEM, Web Based Enterprise Management.
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jdbc2csv.jar
Command-line sql JDBC tool
jdbc2csv is a small command-line tool written in JAVA and can be used on all platforms, for which JRE 8 or higher is available. To connect to a specific DBMS the tool uses its JDBC driver. The result of the executed 'select' query is displayed in CSV format ( different standards are supported ). When there is an error the tool stops with exit code 1 and the error message is output on stderr. jdbc2csv is created with a main purpose to be used in shell-scripts. Relatively easy to configurate, this tool is suitable for queries ‘select’, ‘update’ and ‘delete’. I think that is not suitable for a large number of requests, like 'insert'. -
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ANTLR
Parser generator to read, process, or translate structured text
ANTLR (ANother Tool for Language Recognition) is a powerful parser generator for reading, processing, executing, or translating structured text or binary files. It's widely used to build languages, tools, and frameworks. From a grammar, ANTLR generates a parser that can build and walk parse trees. It’s widely used in academia and industry to build all sorts of languages, tools, and frameworks. Twitter search uses ANTLR for query parsing, with over 2 billion queries a day. The languages for Hive and Pig, the data warehouse and analysis systems for Hadoop, both use ANTLR. Lex Machina uses ANTLR for information extraction from legal texts. Oracle uses ANTLR within SQL Developer IDE and their migration tools. NetBeans IDE parses C++ with ANTLR. The HQL language in the Hibernate object-relational mapping framework is built with ANTLR. -
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FarPlaneTwo
Level-of-Detail renderer in Minecraft. Allows for render distances
FarPlaneTwo is an experimental open-source Minecraft mod that introduces a Level-of-Detail (LoD) terrain rendering system designed to dramatically extend how far players can visually see across the game world. Instead of rendering distant terrain using the same detailed chunk system as nearby areas, the mod generates simplified representations of terrain that require far fewer resources to display. This approach allows players to view landscapes at extremely large distances while maintaining acceptable performance levels. The project aims to support render distances far beyond the limits of the standard Minecraft engine, potentially reaching hundreds of thousands or even millions of blocks. By creating progressively lower-detail versions of terrain farther from the player, the mod can display the shape and structure of distant regions without fully loading those chunks. -
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GanttProject
Official GanttProject repository
GanttProject is a cross-platform desktop application for project scheduling and Gantt chart creation. It allows users to create tasks, assign resources, and track progress with ease. GanttProject is aimed at small teams and individuals who need offline project planning without the complexity or cost of enterprise tools. -
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Grimmory
Grimmory is the successor of booklore
Grimmory is a self-hosted digital library management platform designed to help users organize, read, and manage their entire book collection in a centralized and fully controlled environment. As the successor to Booklore, it expands on the idea of personal knowledge ownership by allowing users to store and interact with books without relying on third-party cloud services. The platform supports a wide range of formats, including eBooks, PDFs, comics, and audiobooks, making it versatile for different types of media consumption. It includes a built-in browser-based reader that allows users to read, annotate, and track progress directly within the application. Grimmory also emphasizes automation through features like metadata enrichment and automatic file ingestion, reducing manual effort when managing large collections. Multi-user support enables separate libraries, preferences, and reading progress for different users within the same instance. -
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Interviews
Comprehensive computer science and interview preparation guide
Interviews is an open source repository designed as a comprehensive guide to preparing for technical interviews, with a strong focus on computer science fundamentals and algorithmic problem solving. Created by Kevin Naughton Jr., the project compiles detailed notes, explanations, and code implementations that cover core areas tested in software engineering interviews. The repository emphasizes topics such as data structures, algorithms, system design, operating systems, databases, and networking. It also includes practical coding examples and solutions that demonstrate how to approach and solve common problems asked at companies like Google, Amazon, Facebook, and Microsoft. By consolidating essential knowledge in one place, the project helps learners efficiently review concepts and practice effectively for interviews. -
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JetBrains Runtime
Runtime environment based on OpenJDK for running IntelliJ products
JetBrainsRuntime is the custom Java Runtime Environment (JRE) distribution maintained by JetBrains that enhances the standard OpenJDK to better support JetBrains products and provide a robust, optimized runtime for IDEs like IntelliJ IDEA, Rider, and other tools. It includes performance-tuned garbage collectors, desktop integration fixes, font rendering improvements, enhanced GTK support on Linux, and additional patches not available in stock JDK builds to ensure smoother, more stable behavior for large-scale IDE usage. These modifications are aimed at reducing resource consumption, improving windowing and high-DPI rendering, and delivering a consistent user experience across operating systems. By controlling the runtime environment, JetBrains can ship their IDEs with confidence that core JVM behavior will align with expected performance, reducing platform-specific issues and enhancing responsiveness. -
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Keycloak
Identity and access management for modern applications and services
Add authentication to applications and secure services with minimum fuss. No need to deal with storing users or authenticating users. It's all available out of the box. You'll even get advanced features such as User Federation, Identity Brokering and Social Login. Keycloak is an open source Identity and Access Management solution aimed at modern applications and services. It makes it easy to secure applications and services with little to no code. Users authenticate with Keycloak rather than individual applications. This means that your applications don't have to deal with login forms, authenticating users, and storing users. Once logged-in to Keycloak, users don't have to login again to access a different application. This also applied to logout. Keycloak provides single-sign out, which means users only have to logout once to be logged-out of all applications that use Keycloak. -
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LeetCode Book
Comprehensive study guide for coding interviews
LeetCode-Book is a comprehensive study guide for coding interviews that consolidates algorithm patterns, data-structure templates, and worked LeetCode solutions. It organizes problems by topic—arrays, linked lists, stacks/queues, trees/graphs, dynamic programming, greedy, backtracking, and math—so you can study systematically. Explanations are concise but intentional, highlighting why a pattern fits, how to reason about boundary cases, and the time/space trade-offs. Many entries include template code and “swap-in” variations, helping you recognize how the same technique adapts across similar problems. The book also emphasizes problem-solving habits like deriving invariants, choosing appropriate data structures, and verifying with small counterexamples. It’s suitable for newcomers building fundamentals and for experienced engineers polishing timing and correctness under interview pressure. -
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Metadata Extractor
Extracts Exif, IPTC, XMP, ICC and other metadata from image and video
metadata-extractor is a Java library for reading metadata from media files. The library understands several formats of metadata, many of which may be present in a single image. -
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OpenJ9
A Java Virtual Machine for OpenJDK
A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR and combines with the Extensions for OpenJDK for OpenJ9 repo. We're not sure which route you might have taken on your way here, but we're really pleased to see you! If you came directly from our website, you've probably already learned a lot about Eclipse OpenJ9 and how it fits into the OpenJDK ecosystem. Eclipse OpenJ9 is an independent implementation of a Java Virtual Machine. "Independent implementation" means it was built using the Java Virtual Machine specification without using any code from any other Java Virtual Machine. The OpenJ9 JVM combines with the Java Class libraries from OpenJDK to create a complete JDK tuned for footprint, performance, and reliability that is well suited for cloud deployments. The original source contribution to OpenJ9 came from the IBM "J9" JVM which has been used in production by thousands of 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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Spring Boot Demo
A project for in-depth study and practical application of Spring Boot
This repository is a hands-on, “deep learning by doing” collection of Spring Boot demos that you can run and study module by module. It currently includes 66 planned integrations (with 55 completed) spanning monitoring, logging, templating, data access, caching, messaging, scheduling, search, security, and more. The master branch targets Spring Boot 2.1.0.RELEASE with a parent POM that centralizes common dependency versions; the older v-1.5.x branch is frozen and its contents are being migrated to master. Each demo ships with its own README and some require pre-initialized database data before launching. The project outlines a standard development environment (JDK 8+, Maven 3.5+, IntelliJ IDEA with Lombok, MySQL 5.7+) and simple run instructions—clone, open in IDEA, import Maven, and run the module’s Application class. It’s intended as a practical reference you can fork, explore, and extend. -
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The Art of Programming
A collection of practical tips can be found at the bottom of this page
The Art of Programming (Second Edition) is a curated collection of programming problems and solutions originally derived from the Microsoft 100 Interview Questions blog series, later refined into a long-running tutorial and ultimately a published book. Created by July, the series began in 2010 and has since evolved into an in-depth exploration of algorithmic thinking, data structures, and coding interview preparation. The repository brings together 42 classic programming problems from the original series, enhanced with detailed explanations, formula derivations, and optimized solutions. In July 2023, work on the second edition was announced, which expands the project with updated content, new problems inspired by recent big-tech interviews, and introductions to modern machine learning techniques such as XGBoost, CNNs, RNNs, and LSTMs. This collection serves both as a historical record of algorithm problem-solving and as a living resource for programmers preparing for interviews. -
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ThingsBoard
Device management, data collection, processing and visualization
ThingsBoard is an open-source IoT platform for data collection, processing, visualization, and device management. It enables device connectivity via industry standard IoT protocols, MQTT, CoAP and HTTP and supports both cloud and on-premises deployments. ThingsBoard combines scalability, fault-tolerance and performance so you will never lose your data. Provision, monitor and control your IoT entities in a secure way using rich server-side APIs. Define relations between your devices, assets, customers or any other entities. Collect and store telemetry data in a scalable and fault-tolerant way. Visualize your data with built-in or custom widgets and flexible dashboards. Share dashboards with your customers. Define data processing rule chains. Transform and normalize your device data. Raise alarms on incoming telemetry events, attribute updates, device inactivity, and user actions. -
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Velocity server
The modern, next-generation Minecraft server proxy
Velocity is a high-performance Minecraft proxy server developed by the PaperMC project that allows multiple Minecraft servers to be linked together into a single network. Acting as an intermediary between players and backend servers, Velocity manages player connections and routes them to different game servers within a network. This architecture allows large Minecraft communities to run multiple servers for different game modes while presenting them as a unified system to players. The software is designed with a focus on performance, scalability, and modern architecture, allowing it to handle thousands of simultaneous players efficiently. Velocity also includes a plugin API that allows developers to extend the proxy with custom functionality and integrate it with existing server tools. Compared with older proxy solutions, the project emphasizes improved performance, reliability, and cleaner software design. -
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X's Recommendation Algorithm
Source code for the X Recommendation Algorithm
The Algorithm is Twitter’s open source release of the core ranking system that powers the platform’s home timeline. It provides transparency into how tweets are selected, prioritized, and surfaced to users, reflecting Twitter’s move toward openness in recommendation algorithms. The repository contains the recommendation pipeline, which incorporates signals such as engagement, relevance, and content features, and demonstrates how they combine to form ranked outputs. Written primarily in Scala, it shows the architecture of large-scale recommendation systems, including candidate sourcing, ranking, and heuristics. While certain components (such as safety layers, spam detection, or private data) are excluded, the release provides valuable insights into the design of real-world machine learning–driven ranking systems. The project is intended as a reference for researchers, developers, and the public to study, experiment with, and better understand the mechanisms behind social media content. -
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XMage
Magic Another Game Engine
XMage allows you to play Magic against one or more online players or computer opponents. It includes full rules enforcement for over 20 000 unique cards and more than 50.000 reprints from different editions. You can also find custom sets like Star Wars. All regular sets have nearly all implemented cards. It supports single matches and tournaments with dozens game modes like duel, multiplayer, standard, modern, commander, pauper, oathbreaker, historic, freeform and much more. Local server supports a special test mode for testing combos and other game situations with pre-defined conditions. There are public servers where you can play XMage against other players. You can also host your own server to play against the AI and/or your friends. Supports special formats like Commander (up to 10 players), Oathbreaker, Cube, Tiny Leaders, Super Standard, Historic Standard and more. -
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Zeebe
Distributed Workflow Engine for Microservices Orchestration
Automate processes at scale with unprecedented performance and resilience. Zeebe is the workflow and decision engine that powers Camunda Platform 8. Zeebe’s cloud-native design provides the performance, resilience, and security enterprises need to future-proof their process orchestration efforts. Zeebe distributes data across all brokers in a cluster with storage directly on the server filesystem. If one broker goes down, another can replace it with no data loss. This pre-configured replication mechanism ensures that Camunda Platform 8 can recover from machine or software failure with no human interaction, no data loss and minimal downtime. -
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WiggleMouse is a cross platform java program that will wiggle the mouse at an interval entered by the user through a gui. For code and latest features please check out https://github.com/samuelskanberg/wigglemouse
