Modrinth · Minecraft mod

Class Loader Fixer

Fixes the Class Loader in legacy Minecraft Forge

Choose a version Pick your version below, then grab the matching file.

Quick answer

Which Class Loader Fixer release should I use?

Updated 2 years ago

Latest stable file 2

Game version 1.3.1, 1.3.2, 1.4

Loader Forge

Class Loader Fixer 2 targets 1.3.1, 1.3.2, 1.4 with Forge. It must be installed on the client. Do not install it on the dedicated server. No extra mods listed for this file.

Where it goes

Is Class Loader Fixer required on the client, server, or both?

It must be installed on the client. Do not install it on the dedicated server.

Client Required

Dedicated server Not supported

Loader for this release Forge

Required install it here Optional supported, not mandatory Not supported do not install here Source doesn’t say do not assume

This file is marked client-only.

Understand client and server requirements Read the Minecraft installation guide

What else does Class Loader Fixer 2 need?

2. Change the file and its required mods may change too.

No extra mods listed for this file

This file does not list any required mods. Do not add a library just because a different file uses it.

This file does not list any required or optional mods.

Before you install it

Add Class Loader Fixer without breaking your instance.

Built for Class Loader Fixer 2. Pick another file and the loader, install side or required mods may change.

01
Stick to this file

Use 2. It targets 1.3.1, 1.3.2, 1.4 with Forge; another release may have different loader, side or dependency requirements.
02
Bring the mods it needs

This file does not list any required mods. Do not add a library just because a different file uses it.
03
Put it on the correct side

It must be installed on the client. Do not install it on the dedicated server.
04
Pick the file you checked

Use the “Get this file” button beside 2. It opens that exact file at the source.

About this project

What does Class Loader Fixer add?

Summary

This mod fixes the Class Loader in legacy versions of Minecraft.

Details

This is a simple jar-mod which adds the CodeSource to each loaded class in FML.
That is actually everything this mod does (well, besides fixing a few more bugs on even older versions of Forge).
This mod just ships a backported RelaunchClassLoader which overwrites the built-in version (from FML) and allows mods to read the file source of classes.

Why is this needed in some cases?

For example, Block Helper is able to show you in the item tooltips which mod a given item is from.
This procedure relies on the CodeSource object of the ProtectionDomains of the loaded classes.
Old versions of FML do not set this CodeSource, which leads Block Helper into thinking that everything is a Vanilla item.

Installation

As a ModLoaderMP / Forge mod

This mod needs to be installed as a jar-mod. That means, you have to...

Be sure to back up your minecraft.jar!
Extract the content of the mod zip into the minecraft.jar file
Delete the META-INF folder in there
Overwrite any existing files when doing so!
???
Profit!

As a Fabric mod

I do not have any Fabric versions available. However, the fix is incorporated directly into Fabricated Legacy Forge. Hence, you do not need to install it separately!