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[1.2.5] Setting up a mod in this really old version?


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Hi there,
I have been looking around for a way to start modding on a Technic SSP, Minecraft version 1.2.5. What I would aim at is to make those big Rubber Trees from RedPower 2 spawn in clusters in normal forests just like they used to in even older versions rather than getting them to spawn singularly and quite far away from each other in the jungles. I would likely be able to handle the code all by myself, even though I have never been modding MC at all, I have a somewhat valuable java knowledge although I might be kind of rusty right now, and I got used to immediately understand this kind of APIs through spigot plugins development, which I've been doing for more than a year, before actually quitting minecraft.

Now, as many of you might already have in mind, 1.2.5 is a highly outdated version that nobody would recommend to neither look for mods of nor to start modding at all, but I really only mind this about my return to minecraft: playing my old days modpacks that I really loved, all on my own. So I wouldn't take anything about updating my game as a solution, I legit don't want to play with anything new of Minecraft, I want my game version to be 1.2.5!

Now, forge's SRC files (yup, there was no Mdk and no gradle back then) are still avaliable for download for mc version 1.2.5, and I already got them.
What you had to do was to extract them inside your MCP (Minecraft Coder Pack) folder, and you also had to move your clean minecraft_server.jar, bin and resources files(folders) inside the jars folder from MCP. I already managed to get myself those files, and I will link you my sources, since they might be known for unreliability in this specific matter or there might be some better copies that you guys know about or own yourselves.
minecraft_server.jar (seemingly very reliable):
  forum: https://www.minecraftforum.net/forums/support/server-support-and/1872947-minecraft-1-2-5-server-jar

  link that i picked (second reply, second link in list labelled "minecraft 1.2.5 server jar"): http://assets.minecraft.net/1_2_5/minecraft_server.jar
bin and resources, .minecraft folder without META-INF folder (which I needed to remove so that was fine):
  YT link: https://www.youtube.com/watch?v=1m92hoZH4Iw

  download link: https://www.youtube.com/redirect?redir_token=rj43zHJV1MhwKy37zYV9oQ7ha6Z8MTU0MDM5NjIzMUAxNTQwMzA5ODMx&event=video_description&v=1m92hoZH4Iw&q=http%3A%2F%2Fwww.mediafire.com%2F%3F1m2j4352e683167

About this .minecraft, I wouldn't know if that's fine to use, and I could download 1.2.5 files from mc's official launcher, but that wouldn't organize them in a bin and resources folder, since it's a little more optimized now and you're not required to have a fully different .minecraft folder in order to play a specific version.

About that bin folder, you also had to install in that minecraft.jar file the Modloader files.
Src: http://www.mediafire.com/file/lnycj6148bf33zs/Modloader+1.2.5.zip


As a last thing, hoping that I didn't forget anything, you also had to put fernflower.jar in the *mcp*\runtime\bin folder, and the way that I got that .jar was simply by grabbing a newer version of mcp (since, after a couple of updates, that file was already included in the directory that i pointed out) and taking the file from its runtime's bin folder.

With all of this said, let's jump to the issue that I'm running into.


After you did all the things listed above correctly, you should run install.cmd, in your forge folder inside mcp; running it is seemingly fine, but at a certain point I encounter a ClassNotFoundException, where the missing class should be "axe" (?):

> Applying Retroguard
'"C:\Program Files\Java\jdk-9.0.1\bin\java" -cp "runtime\bin\retroguard.jar;lib;lib\*;jars\bin\minecr...' failed : 1


Unrecoverable error during obfuscation, see log file for details.
RetroGuard error: COM.rl.obf.classfile.ClassFileException: ClassNotFound axe

Decompile failed
Decompile Exception: 1

This is an error that I didn't usually run into though, I created another fresh mcp folder since I kept on running into weird and deep exceptions, so I preferred to start back from 0, but now this error occurs during the first phase of the setup, it won't really take too long to see it appearing. I'd rather not going back to my first mcp folder, and trying to find solutions to any error I run into on this new one, just to have a clean look at the whole situation rather than going onto something that I had already started which was also quite messy since I had been even running into different kind of errors throughout my discovery on what I had to do about the bin and resources folder and about the minecraft_server.jar and fernflower.jar files.

I'm really clueless on how I should react to any errors right now, and I also feel like I didn't pay enough attention into writing down this post, this is the reason why I hope that you could point me out if I missed anything important to mention.

Any help will be appreciated!

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@Vert3x I'm sorry but that version isn't supported here because of its age. No one on here is going to remember how to set it up or even mod for it.

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I will be posting 1.15.2 modding tutorials on this channel. If you want to be notified of it do the normal YouTube stuff like subscribing, ect.

Forge and vanilla BlockState generator.

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Sorry we don't support 1.2.5 (or any version below 1.9) on this forum anymore due to its age (4+ years old). We simply don't know how to help you anymore. You can go to the Minecraft Forum where I think that they still still support older versions, or update to a modern version of Minecraft (the latest version or the one before it) to receive support on this forum. Your problem might be related to the fact that you need to use Java 8.

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About Me


My Discord - Cadiboo#8887

My WebsiteCadiboo.github.io

My ModsCadiboo.github.io/projects

My TutorialsCadiboo.github.io/tutorials

Versions below 1.14.4 are no longer supported on this forum. Use the latest version to receive support.

When asking support remember to include all relevant log files (logs are found in .minecraft/logs/), code if applicable and screenshots if possible.

Only download mods from trusted sites like CurseForge (minecraft.curseforge.com). A list of bad sites can be found here, with more information available at stopmodreposts.org

Edit your own signature at www.minecraftforge.net/forum/settings/signature/ (Make sure to check its compatibility with the Dark Theme)

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37 minutes ago, Cadiboo said:

Your problem might be related to the fact that you need to use Java 8.

It's probably java 6 as that's really old, but it might be java 7. Definitely not 8.

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I will be posting 1.15.2 modding tutorials on this channel. If you want to be notified of it do the normal YouTube stuff like subscribing, ect.

Forge and vanilla BlockState generator.

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7 hours ago, Animefan8888 said:

that version isn't supported here because of its age.


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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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