BReversed

A java bytecode deobfuscator

Project Setup

Prerequisites

• java 21+
• git

Cloning Project & Dependencies

Clone BReversed and the required dependencies:

git clone https://github.com/Exeos/BReversed.git
git clone https://github.com/Exeos/ASMPlus.git

⚠️ Before you continue: Setup ASMPlus as described in its README

Resulting layout:

/
├── BReversed/
└── ASMPlus/

Make a local gradle properties file from the example and update the dependency paths. From the BReversed directory run:

cp gradle.properties.example gradle.properties

Open gradle.properties and set the dependency paths (these are the defaults you can use if the repos are siblings as shown above):

dependencies.asmplus.path=../ASMPlus

Building the Project

BReversed uses Gradle Composite Builds to include ASMPlus and jlib. After cloning and configuring gradle.properties, build from the BReversed directory:

Unix / macOS:

./gradlew build

Windows:

gradlew.bat build

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Config

BReversed is driven by a JSON configuration file. Create a config.json in the working directory you run BReversed from.

Example template

{
  "task": "DETECT",

  "path": "jars",
  "input": "in.jar",
  "output": "out.jar",

  "renamerString": "BReversed",

  "transformers": [
    "crasher/IMGCrasherRemover",
    "bozar/",
    "!BozarLightFlow"
  ]
}

Fields explained

• task

  • "DETECT" — analyze the input and print detected obfuscators.
  • "TRANSFORM" — run configured transformers and write the transformed jar to output.

• path

  • Optional. Directory where jars live (relative to working directory).

• input

  • The input jar file name (the .jar extension is optional). Example: "in.jar" or "in".

• output

  • The output jar file name (the .jar extension is optional). When task is "TRANSFORM", the processed jar will be written here.

• renamerString

  • Base string used when renaming members (classes, fields, methods). Indices may be appended.

• transformers

  • Array of transformers to apply when task is "TRANSFORM".
  • Format notes:
    • "packagename/TransformerSimpleName" — enable a single transformer.
    • "packagename/" — enable all transformers in that package.
    • "!TransformerSimpleName" — exclude a transformer (negation).
  • Order matters: transformers are applied in the listed order unless there is a Comparator for the transformer(s) parent package.

Tips & Best Practices

• Start with "DETECT" to understand what protections are present before running transforms.
• Use !Transformer entries to exclude known-bad or unstable transformers.

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