ZombieBuddy

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Author: Zed

Last revision: 7 May at 07:13 UTC (5)

File size: 14.46 MB

On Steam Workshop

Description:

A framework that enables advanced Java mods for Project Zomboid.

What it does:
ZombieBuddy is required by some mods to work. If a mod tells you to install ZombieBuddy, follow the instructions below.

Installation (One-Time Setup)

Step 1: Subscribe to ZombieBuddy on Steam Workshop

Step 2: Installation is required ONLY ONCE for ZombieBuddy itself.

🪟 Windows:

Option A: Automated Installer (Recommended)

  • Download the latest ZombieBuddyInstaller.exe from GitHub Releases[github.com]
  • Run the installer and choose Install or update ZombieBuddy.
  • Choose what launch mode to patch:
    • Both (recommended): patches Normal Launch and Alternate Launch.
    • Normal Launch: then choose ProjectZomboid64.json, Steam launch options, or both.
    • Alternate Launch: patches ProjectZomboid64.bat.
  • The installer shows every system change first and asks for confirmation before applying it.
  • If Steam launch options need to be changed, the installer will ask you to close Steam at that point.
  • The same installer can also uninstall ZombieBuddy later: run it again and choose Uninstall ZombieBuddy.

Option B: Manual Installation

  • Copy ZombieBuddy.jar and zbNative.dll from:
    C:Program Files (x86)Steamsteamappsworkshopcontent1086003619862853modsZombieBuddylibs

    to your Project Zomboid folder:

    C:Program Files (x86)SteamsteamappscommonProjectZomboid
  • Open Project Zomboid’s launch options in Steam
  • Add this launch option:
    -agentlib:zbNative —
  • ⚠️ IMPORTANT: The — at the end is mandatory – do not omit it!
  • If you use the game’s Alternate Launch option on Windows, set the ProjectZomboid64.bat _JAVA_OPTIONS line to:
    SET _JAVA_OPTIONS=-agentlib:zbNative

🍎 macOS / 🐧 Linux:

  • Copy ZombieBuddy.jar from the mod’s libs/ directory to:
    • macOS: ~/Library/Application Support/Steam/steamapps/common/ProjectZomboid/Project Zomboid.app/Contents/Java/
    • Linux: ~/.steam/steam/steamapps/common/ProjectZomboid/projectzomboid/
  • Open Project Zomboid’s launch options in Steam
  • Add this JVM argument: -javaagent:ZombieBuddy.jar —
  • ⚠️ IMPORTANT: The — at the end is mandatory – do not omit it!

Step 3: After this setup, all mods that require ZombieBuddy will work automatically!

Uninstall
  • Disable the agent first: Open Project Zomboid → Properties → clear the Launch Options line
  • Delete zbNative.dll and ZombieBuddy.jar from your Project Zomboid install directory
  • Unsubscribe from ZombieBuddy on Steam

⚠️ Security Warning ⚠️

Java mods enabled through ZombieBuddy have unrestricted access to your system. Only install mods from sources you trust.

No jar will sneak in. Whenever a Java mod ships a new or updated JAR, ZombieBuddy shows a native dialog with the mod id, file path, last-modified date, and SHA-256 fingerprint. Nothing is loaded until you click Yes. You can choose to remember the decision (per-mod, per-hash) or keep it session-only. Persisted allow/deny choices are written to JSON (mod id → { sha256 → true|false }) at:

  • Windows: %USERPROFILE%.zombie_buddymod_approvals.json
  • macOS / Linux: ~/.zombie_buddy/mod_approvals.json

If a previously-approved JAR changes on disk (hash mismatch), you will be prompted again.
Tip: hold Shift during game load to force the approval dialog to appear, even for previously approved Java mods.

Java Mod Policy

Controls what happens when an unknown/changed JAR is seen. Pass as a policy=… argument:

  • prompt (default) – ask me each time via a native dialog.
  • deny-new – silently skip any JAR that isn’t already approved.
  • allow-all – load every JAR without prompting. Not recommended.

Examples (block form, these go into Steam launch options):

-agentlib:zbNative=policy=deny-new — (Windows) -javaagent:ZombieBuddy.jar=policy=deny-new — (macOS / Linux)

FAQ
  • Is it a virus?
    No.
  • How to start game in debug mode?
    -agentlib:zbNative — -debug OR -javaagent:ZombieBuddy.jar — -debug

  • Do I need to repeat manual installation after I upgrade/downgrade/validate game?
    No, if you use the default launcher and have agentlib in Steam launch options.
    Yes, if ZombieBuddy stops loading.
  • Works on MP?
    Yes.
  • Save compatibility?
    Safe to add or remove on existing saves.
  • I clicked the wrong button in the approval dialog. How do I reset it?
    Open mod_approvals.json (path above), under ‘mods’ find your mod id, then remove or edit the SHA-256 key you want to reset (or change true/false), save, and restart.
  • Can I see which Java mods were loaded or blocked?
    Yes – install Zed’s Better ModList and the status is shown next to each JAR path in the mod list.
  • Supported game versions?
    B41, B42.12-B42.17
  • Can I hide ZB watermark?
    Yes, in ModOptions. During game boot it is always visible.
  • WHY ALL LINKS ARE REMOVED FROM THIS PAGE AND COMMENTS DISABLED???!!!
    Steam does that while it checks a newly uploaded mod version for viruses, I suppose. Everything should return to normal in 10..30 minutes, depending on how busy their system is.

Links

GitHub Repository[github.com]

Support the Project

If you find ZombieBuddy useful, consider supporting its development:
[ko-fi.com]

Workshop ID: 3619862853
Mod ID: ZombieBuddy

Download
Revisions:

Old revisions of this mod are available below. Click the link to download.