How to decompile minecraft mod

SimplyProgrammer/Minecraft-Deobfuscator3000

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Deobfuscator3000 is a universal tool for deobfuscating minecraft mods! It meant to be upgraded and improved variant of BON that was abandoned by its authors a long time ago. Compare to BON this one allows you to choose obfuscation mappings by your self and it can decompile and deobfuscate your mod all at once! Deobfuscator3000 can also deobfuscate individual java files and it can also works with zip files not only jars! It also has more user-friendly UI with tooltips, logging console and other things!
Deobfuscator3000 is perfect choice for minecraft modders that lost their source code or for anyone that is interested in sources of other mods!

Since application was wrapped into installer and procyon decompiler was implemented, using procedure is now far easier!

Valid deobfuscation mappings composition

About

Powerful and universal deobfuscator for Minecraft mods and java decompiler!

Minecraft Forums

Java Decompiling Forge Mods

What is the best way to decompile forge mods? The reason I want to know is because I lost the source code for a mod I was developing last year and there are a few bugs I need to fix. Is there a good way of doing this, or will I need to start over from scratch?

Use BON to deobfuscate the JAR and then use a regular Java decompiler to decompile it.

Some decompilers that I know of:

I’ve found Procyon and CFR to be the most reliable, though both have issues with some mods (especially ones written in Scala instead of Java).

Chisel Facades: For all your decorative pipe-hiding needs.

Please don’t PM me to ask for help or to join your mod development team. Asking your question in a public thread preserves it for people who are having the same problem in the future. I’m not interested in developing mods with people.

BON is giving me this error and I can’t figure out what I need to fix it.

This issue has been reported by someone on GitHub, but immibis hasn’t responded to it. At some point Forge started adding 1.7.10 as a suffix of the full version; BON is trying to download the Forge JAR without adding the suffix, so it’s getting a 404.

I’d recommend using the command line interface instead of the GUI. To prepare your environment, you’ll need to do the following:

You can then deobfuscate a Forge mod using this command (substituting the appropriate paths)

Chisel Facades: For all your decorative pipe-hiding needs.

Please don’t PM me to ask for help or to join your mod development team. Asking your question in a public thread preserves it for people who are having the same problem in the future. I’m not interested in developing mods with people.

Choonster-Minecraft-Mods/MinecraftModDecompiler

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README.md

This project has been discontinued. I recommend using BON2 to deobfuscate mods and a regular Java decompiler to decompile them.

Minecraft Mod Decompiler

Decompiles and deobfuscates all Minecraft Forge mods in a specified directory and outputs the source files to another directory.

Please respect the individual mod licenses when using this tool.

This tool uses JD-Core-java for decompilation.

JD itself supports:

The idea and eclipse Gradle plugins are included in the build script, so you can run gradlew idea or gradlew eclipse to generate an IDE project.

For convenience, the included MCModDecompiler batch/shell scripts can be run with the same arguments after building in a cloned repository.

The MCP mapping files can be found in the MCP releases under the conf directory. If you’ve set up a ForgeGrqadle workspace, you can also find the mapping files in your Gradle cache (

/.gradle/caches/minecraft/net/minecraftforge/forge/ /unpacked/conf for Minecraft 1.7.2 and later).

MinecraftModDecompiler is released under the MIT license. See LICENSE.txt for details.

JD-IntelliJ (included with JD-Core-java) is free for non-commercial use. This means that JD-IntelliJ shall not be included or embedded into commercial software products. Nevertheless, this tool may be freely used for personal needs in a commercial or non-commercial environments.

About

[DISCONTINUED] A tool to batch decompile and deobfuscate Minecraft Forge mods.

Minecraft Forums

How do I decompile and deobfuscate a mod?

looking to do this on my old mod and use whatever code I can use for the 1.12.2 version.

This may not work with Forge mods but I was able to decompile Optifine by decompiling a modded jar, as well as a modded jar including both Optifine and one of my own mods; either way, as it is all Java code you could just place your mod’s files into the Minecraft jar (in a sub-folder so they aren’t mixed up with the vanilla files) and decompile it; you’ll certainly get errors when it tries to recompile it but all that matters is the decompiled code (in my case it actually recompiled and ran without any issues once I deleted the Optifine installer files (I just install Optifine directly into the jar, not using its installer; the files do not cause any issues when playing since they are not referenced by any running code) since the mods were jar mods with no dependence on a mod loader or external libraries).

You could also use a tool like JD-GUI, although it won’t be deobfuscated (your own code shouldn’t be obfuscated but any references to Minecraft code will be) and it may have issues with code complied on newer Java versions (it technically only supports up to Java 5 but I’ve used it to decompile versions up to 1.13 snapshots); for example, it uses odd characters in place of the sizes of arrays in this code (compiled to Java 6, which MCP for 1.6.4 works with).

Also, in either case comments will be missing since they are not included in compiled classes, so you may have to figure out what the code does given the aforementioned decompilation bugs (there may be better decompilers).

Minecraft Forums

Best way to decompile a forge mod?

Recently I found a mod which was abandoned and upon seeing it I go in communication with the owner. He gave me permission but then said he didn’t have the source code so I would need to decompile it. I looked at JD GUI and JAD but they leave thousands of errors so I ask is there any better way to decompile it without so many errors?

When I’m looking in mods I’m using JD GUI and then rewrite the code by reading it and fixing what I can. I was doing this with the Block Mover from Random Things becuse the item is not in the mod now. In that way you can also learn modding

I know modding but 2000+ errors from JD GUI I mean if it comes down to it I might do it but eh the least errors I can get is better.

I did that and it had around 3000 errors.

I’ve never decompiled a mod but is the project set up correctly with all of the valid libraries referenced? You get a few thousand errors if you try to make a MCP project without setting up the libraries, so just a guess in the dark.

I did that and it had around 3000 errors.

What kind of errors?

What kind of errors?

Things like duplicate names and alot of renamed variables

Things like duplicate names and alot of renamed variables

Okay, specifically what kind of errors? Examples?

Alot don’t show till fixing alot of them but

Alot don’t show till fixing alot of them but

It seems that you didn’t de-obfuscate the code correctly.

It seems that you didn’t de-obfuscate the code correctly.

I did the exact same steps as in the video made by one of the staff members using bon.

you need to match up the fields and and functions shown in jd gui with the fields and functions from that version to decrypt it then port them over to the new version. most of the time they are the same but when there is stuff that has been taken out / changed in newer versions its harder

Use the «local MCP» option in BON, and ensure your MCP installation is set to use recent mappings from MCPBot.

There is also a chance that the developer of your mod applied their *own* obfuscation to prevent people like you from stealing their code

There might be better accuracy in using fernflower from MCP since they modify it but I don’t know how.

Use the «local MCP» option in BON, and ensure your MCP installation is set to use recent mappings from MCPBot.

There is also a chance that the developer of your mod applied their *own* obfuscation to prevent people like you from stealing their code

There might be better accuracy in using fernflower from MCP since they modify it but I don’t know how.

To answer line 2 I’m not stealing the developer quit development and deleted his src. I asked him for permission to continue development and he said the only way to get the source would be to decompile.