Browse free open source Java Games and projects below. Use the toggles on the left to filter open source Java Games by OS, license, language, programming language, and project status.

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  • 1
    Xonotic

    Xonotic

    Superproject containing build scripts and tools to download assets

    Xonotic is a free, open-source arena-style first-person shooter video game that emphasizes fast-paced movement, skill-based combat, and a diverse arsenal, with gameplay reminiscent of classic shooters like Quake and Unreal Tournament. Born as a community fork of the Nexuiz project to preserve open development principles, Xonotic runs on an enhanced version of the DarkPlaces engine and supports Windows, macOS, and Linux platforms with no installation required beyond extracting the game files. Players can enjoy a wide variety of multiplayer game modes—from traditional deathmatch and team captures to experimental variations like Nexball and Freeze Tag—each designed to exploit high mobility and deep map knowledge. The game includes dozens of official and community-created maps, robust server browsing, customizable HUD and controls, and even an integrated statistics system called XonStat for tracking performance.
    Downloads: 11 This Week
    Last Update:
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  • 2
    MotorAssistance

    MotorAssistance

    Aim assistance for blocks and mobs

    AimAssistanceMod is a Minecraft modification that provides aim assistance for interacting with blocks and mobs. It is particularly beneficial for players using controllers or those with disabilities, as it enhances the gameplay experience without offering any advantage in player-versus-player (PvP) scenarios. The mod is fully configurable, allowing users to tailor the assistance to their preferences.
    Downloads: 10 This Week
    Last Update:
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  • 3
    Slimefun 4

    Slimefun 4

    A unique Spigot/Paper plugin that looks and feels like a modpack

    A Minecraft plugin adds hundreds of new features, such as advanced machines and magic, to enhance vanilla gameplay.
    Downloads: 10 This Week
    Last Update:
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  • 4
    Jin is a Java client for various chess servers. It currently supports the Internet Chess Club (chessclub.com) and the Free Internet Chess Server (freechess.org) but is designed to be able to support any chess server.
    Downloads: 53 This Week
    Last Update:
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  • 5
    MAME4droid

    MAME4droid

    MAME Android Emulator.

    MAME4droid (0.139u1) is developed by David Valdeita (Seleuco), port of MAME 0.139u1 emulator by Nicola Salmoria and TEAM. MAME4droid (0.139u1) emulates arcade games supported by original MAME 0.139u1. This MAME4droid version is targeted to Dual-Core devices, because it is based on a high specs 2010 PC MAME build. Anyway don't expect arcade games of the 90 to work at full speed. With some games that are really bad optimized (like outrun or mk series) you will need at least a 1.5 ghz dual-core device (Cortex A15). This is related to MAME build used, since it is targeted to high specs PC's as i said before. This version emulates over 8000 different romsets. Please, try to understand that that with that amount of games, some will run better than others and some might not even run with MAME4droid. Please, don't email me asking for a specific game to run. Official web page for news, source code & additional information: http://code.google.com/p/imame4all/
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    Downloads: 66 This Week
    Last Update:
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  • 6
    XMage

    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.
    Downloads: 9 This Week
    Last Update:
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  • 7
    GrimAC

    GrimAC

    Fully async, multithreaded, predictive, open source, 3.01 reach

    GrimAC is an open-source anticheat system designed to detect and prevent cheating on Minecraft multiplayer servers through predictive simulation and advanced movement analysis. The project uses a simulation-based detection engine that recreates player movement and physics in order to identify discrepancies between legitimate gameplay and modified client behavior. By analyzing how players move, interact with the world, and send network packets to the server, Grim can detect a variety of cheats such as reach hacks, speed hacks, and anti-knockback modifications. The software is designed to operate asynchronously and with multithreaded processing, allowing servers to maintain high performance even when monitoring large numbers of players simultaneously. Grim supports a wide range of Minecraft versions and can integrate with server platforms used in competitive or large multiplayer environments.
    Downloads: 8 This Week
    Last Update:
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  • 8
    PCGen :: An RPG Character Generator

    PCGen :: An RPG Character Generator

    RPG character generator for RPG d20 systems.

    PCGen is a free open source RPG character generator (d20 systems). All datafiles are ASCII so they can be modified by users for their own campaigns. Please join us at http://groups.yahoo.com/group/pcgen/. Support email: help@pcgen.org
    Downloads: 33 This Week
    Last Update:
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  • 9
    FarPlaneTwo

    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.
    Downloads: 7 This Week
    Last Update:
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  • 10
    ViaVersion

    ViaVersion

    Allows the connection of newer clients to older server versions

    Allows the connection of higher client versions to lower server versions - it works on any platform you can think of. The base ViaVersion jar runs on Paper and Velocity. We also have projects integrating ViaVersion to run on Fabric, Forge, Bungee, Sponge, or as a standalone proxy to join from basically any client version on any server version from the past decade. See HERE for an overview of the different Via* projects. Note that ViaVersion will be able to run best on either Paper servers or through ViaFabricPlus due to having direct access to client/server state and more extensive API.
    Downloads: 7 This Week
    Last Update:
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  • 11
    VASSAL Engine
    VASSAL is a game engine for creating electronic versions of traditional board and card games. It provides support for game piece rendering and interaction, and supports play by email or over a live connection.
    Downloads: 32 This Week
    Last Update:
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  • 12
    MegaMek
    MegaMek is a networked Java clone of BattleTech, a turn-based sci-fi boardgame for 2+ players. Fight using giant robots, tanks, and/or infantry on a hex-based map. Development currently occurs on GitHub (see https://github.com/MegaMek). This SF page remains as a mirror and archive of the old issue trackers. The trackers are currently locked and new issues should be created on the GitHub page.
    Downloads: 29 This Week
    Last Update:
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  • 13
    jMonkeyEngine

    jMonkeyEngine

    A complete 3-D game development suite written in Java

    jMonkeyEngine is a 3-D game engine for adventurous Java developers. It’s open-source, cross-platform, and cutting-edge. v3.6.1 is the latest stable version of the engine. The engine is used by several commercial game studios and computer-science courses.
    Downloads: 6 This Week
    Last Update:
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  • 14
    minecraft-world-downloader

    minecraft-world-downloader

    Download Minecraft worlds, extend server's render distance. 1.12.2

    A Minecraft world downloader that works as a proxy server between the client and the server to read & save chunk data. Download multiplayer worlds by connecting to them and walking around. Chunks can be sent back to the client to extend the render distance.
    Downloads: 6 This Week
    Last Update:
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  • 15
    Crossfire RPG game

    Crossfire RPG game

    Cooperative multiplayer graphical RPG and adventure game

    Crossfire is a free and open-source cooperative multiplayer graphical RPG and adventure game. Set in a medieval fantasy world, it combines real-time action with traditional role-playing mechanics inspired by games such as Gauntlet, NetHack, Moria, and Angband. Players can choose from 14 races and 16 character classes, develop skills and magic, worship gods, complete quests, discover powerful artifacts, and explore thousands of interconnected maps filled with monsters, dungeons, cities, and adventures. Crossfire has been continuously developed since 1992 and remains an actively maintained community project.
    Downloads: 40 This Week
    Last Update:
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  • 16
    Corewar is a game played vicariously through the action of assembly language programs written in a language called Redcode. Corewar is discussed in the Usenet group REC.GAMES.COREWAR; the reference implementation of this game, pMARS, is maintained here.
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    Downloads: 47 This Week
    Last Update:
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  • 17
    Crystal Space 3D SDK
    Crystal Space is an Open Source 3D SDK for Unix, Windows, and MacOS/X. It renders with OpenGL and features GLSL shaders, CG shaders, deferred rendering, dynamic shadows, bullet based physics library, terrain engine, skeleton based animation meshes, exporter for Blender, portals, etc...
    Downloads: 27 This Week
    Last Update:
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  • 18
    Nukkit

    Nukkit

    Nuclear-Powered Minecraft: Bedrock Edition Server Software

    Nukkit is nuclear-powered server software for Minecraft: Pocket Edition. It has a few key advantages over other server software.
    Downloads: 5 This Week
    Last Update:
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  • 19
    Colossus is a Java clone of the boardgame Titan, a turn-based fantasy wargame for 2-6 players. Each player moves stacks of creatures around a strategic board, recruiting more creatures and fighting enemy stacks on tactical maps.
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    Downloads: 33 This Week
    Last Update:
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  • 20
    JSoko

    JSoko

    The Sokoban game implemented in Java.

    JSoko is a Java program for playing the Sokoban game. It features path finding, auto push, auto solving, undo/redo, deadlock detection, and more.
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    Downloads: 27 This Week
    Last Update:
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  • 21
    Aurora Game Hub

    Aurora Game Hub

    Experience your PC Games Beautifully. Try it, we think you'll like it.

    ======================== Welcome! =========================== Experience your PC Game Library Beautifully. Try it, we think you'll like it. Check out our new video! http://www.youtube.com/watch?v=GHeQP8dNlvU Aurora Game Hub is something we made out of hate for the current PC Gaming experience. We Love Playing PC Games. We really love gaming on the PC. We think using the awesome power and flexibility of PC and using inspiration from the elegant and beautiful experience from Consoles we can make something pretty cool. This is still a work in progress! So if you find any bugs please go here to report them: http://www.auroragamehub.com/support Thank you for your time! -- CC BY-NC-ND 3.0
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    Downloads: 32 This Week
    Last Update:
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  • 22
    FS2004/FSX Scenery Config Editor
    A java based Scenery Config Editor. Provides group functionality and more.
    Downloads: 22 This Week
    Last Update:
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  • 23
    Botania

    Botania

    A tech mod for Minecraft themed around the magic of nature

    Botania is a Minecraft tech mod themed around natural magic. It's inspired by other magic mods, such as Thaumcraft or Blood Magic. With an original aim- and timing-based power system, Botania has a very different feel from your typical magic or tech mod. Manipulating Mana and watching it flow in real time adds a new light to your base of operations. Botania works within the Minecraft world itself; no GUIs are used to interact with any of its features. It's carefully designed to ensure that nearly everything is fully automatable using vanilla and itself. After some thought, of course. The Lexica Botania is the compendium of nearly all knowledge about this mod. Easily craftable in-game using a book and a sapling, it gives you almost all the information you'll ever need to know about Botania.
    Downloads: 4 This Week
    Last Update:
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  • 24
    Grasscutter

    Grasscutter

    A server software reimplementation for a certain anime game

    Grasscutter is an open-source Java server reimplementation for a certain anime-style online game, created for private server emulation and research. It uses Java 17, MongoDB, and Gradle, and it has an ecosystem that includes documentation, a launcher, plugins, and community tooling. The project allows users to run a compatible server environment for specific supported game client versions, but it is not actively maintained in the same way it once was. Current documentation warns that version matching matters and that support is limited, especially beyond the older supported release range. Grasscutter is most relevant to developers interested in reverse engineering, server emulation, game protocol research, and modding communities. Because it interacts with proprietary game clients and services, it should be used only in lawful, authorized, and non-commercial contexts.
    Downloads: 4 This Week
    Last Update:
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  • 25
    Grimmory

    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.
    Downloads: 4 This Week
    Last Update:
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