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Complete Newbie, Followed Tutorial, How Do I Build a jar


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I followed a tutorial to make a patch between two mods. I now have a folder that looks like this.

I have essentially zero experience writing mods, using Forge, or using Gradle, which I know is less than basically everyone here, but I don't know where else to go. All I want to do is package this into a .jar and add it to my game. How do I do that?

I have tried opening a command line and running 'gradlew build' in this folder, as suggested by this minecraft forums thread.  The build ran for a while and then failed. The output is here. The issues seem to be that it couldn't find 'tools.jar' and 'net.minecraftforge:forge:1.16.4-35.1.0_mapped_snapshot_20201028-1.16.3'.


What should I do? To be clear, at the moment I am less interested in making a larger project or learning general Forge skills than I am in solving this immediate problem. All I want to do right now is install this patch so I can start using these mods together. I would greatly appreciate clear and easy-to-follow steps. Thank you for the help.

Edited by Syric
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Sorry about that, I know it's phrased badly. I do have a basic understanding of Java- just enough to do what little writing this project required. I'm not unwilling to learn, I'm just prioritizing immediately actionable advice over general skills. I said it because I've spent the last couple hours reading tutorials about general Forge modding skills and I just really, really need a list of steps to follow at this point.

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Okay, I've put some time into it and I now have things running okay (I think)- I have JDK 8, and I'm using Intellij IDEA. My mod builds successfully. I have been told that the output .jar file is in build/libs, but the libs folder doesn't exist. My build folder looks like this. Have I done something wrong? 



I set up a jar artifact and compiled successfully, but it crashes the game on startup. This is the log file:

image.thumb.png.97805cae2d9d6445868910c07f38b04d.pngI suspect that it did not, in fact, compile successfully. My guess is that I set up the artifact wrong. What should I do?

Edited by Syric
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My mod now runs and functions perfectly when I launch Minecraft using 'gradlew runClient', which that link suggested for testing. However, when I take the jar I made with 'gradlew build' and put it in my Forge mods folder, Minecraft does not launch- I get this error instead.
For reference, my mod is 'Undergarden/Tetra Patch' and 'tetra' is one of the mods I'm attempting to work with.


Full crash log available here.

If anyone knows how to fix this error specifically, that's great, but the question I think would be easier to answer is 'why does this work with gradlew runClient but not in normal Minecraft'?


Thanks for your help. 

Edited by Syric
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When you tried to run your mod outside of development did you also remember to add the mod you're using into the mod folder?

This is my Forum Signature, I am currently attempting to transform it into a small guide for fixing easier issues using spoiler blocks to keep things tidy.


As the most common issue I feel I should put this outside the main bulk:

The only official source for Forge is https://files.minecraftforge.net, and the only site I trust for getting mods is CurseForge.

If you use any site other than these, please take a look at the StopModReposts project and install their browser extension, I would also advise running a virus scan.


For players asking for assistance with Forge please expand the spoiler below and read the appropriate section(s) in its/their entirety.


Logs (Most issues require logs to diagnose):


Please post logs using one of the following sites (Thank you Lumber Wizard for the list):

https://gist.github.com/100MB Requires member (Free)

https://pastebin.com/: 512KB as guest, 10MB as Pro ($$$)

https://hastebin.com/: 400KB

Do NOT use sites like Mediafire, Dropbox, OneDrive, Google Drive, or a site that has a countdown before offering downloads.


What to provide:

...for Crashes and Runtime issues:

Minecraft 1.14.4 and newer:

Post debug.log

Older versions:

Please update...


...for Installer Issues:

Post your installer log, found in the same place you ran the installer

This log will be called either installer.log or named the same as the installer but with .log on the end

Note for Windows users:

Windows hides file extensions by default so the installer may appear without the .jar extension then when the .log is added the log will appear with the .jar extension


Where to get it:

Mojang Launcher: When using the Mojang launcher debug.log is found in .minecraft\logs.


Curse/Overwolf: If you are using the Curse Launcher, their configurations break Forge's log settings, fortunately there is an easier workaround than I originally thought, this works even with Curse's installation of the Minecraft launcher as long as it is not launched THROUGH Twitch:

  1. Make sure you have the correct version of Forge installed (some packs are heavily dependent on one specific build of Forge)
  2. Make a launcher profile targeting this version of Forge.
  3. Set the launcher profile's GameDir property to the pack's instance folder (not the instances folder, the folder that has the pack's name on it).
  4. Now launch the pack through that profile and follow the "Mojang Launcher" instructions above.






or alternately, 


Fallback ("No logs are generated"):

If you don't see logs generated in the usual place, provide the launcher_log.txt from .minecraft


Server Not Starting:


If your server does not start or a command window appears and immediately goes away, run the jar manually and provide the output.


Reporting Illegal/Inappropriate Adfocus Ads:


Get a screenshot of the URL bar or copy/paste the whole URL into a thread on the General Discussion board with a description of the Ad.

Lex will need the Ad ID contained in that URL to report it to Adfocus' support team.


Posting your mod as a GitHub Repo:


When you have an issue with your mod the most helpful thing you can do when asking for help is to provide your code to those helping you. The most convenient way to do this is via GitHub or another source control hub.

When setting up a GitHub Repo it might seem easy to just upload everything, however this method has the potential for mistakes that could lead to trouble later on, it is recommended to use a Git client or to get comfortable with the Git command line. The following instructions will use the Git Command Line and as such they assume you already have it installed and that you have created a repository.


  1. Open a command prompt (CMD, Powershell, Terminal, etc).
  2. Navigate to the folder you extracted Forge’s MDK to (the one that had all the licenses in).
  3. Run the following commands:
    1. git init
    2. git remote add origin [Your Repository's URL]
      • In the case of GitHub it should look like: https://GitHub.com/[Your Username]/[Repo Name].git
    3. git fetch
    4. git checkout --track origin/master
    5. git stage *
    6. git commit -m "[Your commit message]"
    7. git push
  4. Navigate to GitHub and you should now see most of the files.
    • note that it is intentional that some are not synced with GitHub and this is done with the (hidden) .gitignore file that Forge’s MDK has provided (hence the strictness on which folder git init is run from)
  5. Now you can share your GitHub link with those who you are asking for help.

[Workaround line, please ignore]


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