proguard

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Quick Start • Features • Contributing • License

ProGuard is a free shrinker, optimizer, obfuscator, and preverifier for Java bytecode:

• It detects and removes unused classes, fields, methods, and attributes.

• It optimizes bytecode and removes unused instructions.

• It renames the remaining classes, fields, and methods using short meaningless names.

The resulting applications and libraries are smaller, faster, and a bit better hardened against reverse engineering. ProGuard is very popular for Android development, but it also works for Java code in general.

❓ Getting Help

If you have usage or general questions please ask them in the Guardsquare Community.
Please use the issue tracker to report actual bugs 🐛, crashes, etc.

🚀 Quick Start

ProGuard has its own Gradle plugin, allowing you to shrink, optimize and obfuscate Android projects.

ProGuard Gradle Plugin

You can apply the ProGuard Gradle plugin in AGP 4+ projects by following these steps:

1. Add a classpath dependency in your root level build.gradle file:

buildscript {
    repositories {
        google()       // For the Android Gradle plugin.
        mavenCentral() // For the ProGuard Gradle Plugin and anything else.
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:x.y.z'    // The Android Gradle plugin.
        classpath 'com.guardsquare:proguard-gradle:7.2.1'  // The ProGuard Gradle plugin.
    }
}

2. Apply the proguard plugin after applying the Android Gradle plugin as shown below:

 apply plugin: 'com.android.application'
 apply plugin: 'com.guardsquare.proguard'

3. ProGuard expects unobfuscated class files as input. Therefore, other obfuscators such as R8 have to be disabled.

android {
    ...
    buildTypes {
       release {
          // Deactivate R8.
          minifyEnabled false
       }
    }
}

4. Configure variants to be processed with ProGuard using the proguard block:

android {
    ...
}

proguard {
   configurations {
      release {
         defaultConfiguration 'proguard-android-optimize.txt'
         configuration 'proguard-project.txt'
      }
   }
}

You can then build your application as usual:

gradle assembleRelease

The repository contains some sample configurations in the examples directory. Notably, examples/android has a small working Android project that applies the ProGuard Gradle plugin.

Integrated ProGuard (AGP < 7.0)

If you have an older Android Gradle project you can enable ProGuard instead of the default R8 compiler:

1. Disable R8 in your gradle.properties:

android.enableR8=false
android.enableR8.libraries=false

2. Override the default version of ProGuard with the most recent one in your main build.gradle:

buildscript {
    //...
    configurations.all {
        resolutionStrategy {
            dependencySubstitution {
                substitute module('net.sf.proguard:proguard-gradle') with module('com.guardsquare:proguard-gradle:7.2.1')
            }
        }
    }
}

3. Enable minification as usual in your build.gradle:

android {
    //...
    buildTypes {
        release {
            minifyEnabled   true
            shrinkResources true
            proguardFile getDefaultProguardFile('proguard-android-optimize.txt')
            proguardFile 'proguard-project.txt'
        }
    }
}

4. Add any necessary configuration to your proguard-project.txt.

You can then build your application as usual:

gradle assembleRelease

The repository contains some sample configurations in the examples directory. Notably, examples/android-agp3-agp4 has a small working Android project that uses the old integration.

✨ Features

ProGuard works like an advanced optimizing compiler, removing unused classes, fields, methods, and attributes, shortening identifiers, merging classes, inlining methods, propagating constants, removing unused parameters, etc.

• The optimizations typically reduce the size of an application by anything between 20% and 90%. The reduction mostly depends on the size of external libraries that ProGuard can remove in whole or in part.

• The optimizations may also improve the performance of the application, by up to 20%. For Java virtual machines on servers and desktops, the difference generally isn't noticeable. For the Dalvik virtual machine and ART on Android devices, the difference can be worth it.

• ProGuard can also remove logging code, from applications and their libraries, without needing to change the source code — in fact, without needing the source code at all!

The manual pages (markdown, html) cover the features and usage of ProGuard in detail.

💻 Building ProGuard

Building ProGuard is easy - you'll just need a Java 8 JDK installed. To build from source, clone a copy of the ProGuard repository and run the following command:

./gradlew assemble

The artifacts will be generated in the lib directory. You can then execute ProGuard using the scripts in bin, for example:

bin/proguard.sh

You can publish the artifacts to your local Maven repository using:

./gradlew publishToMavenLocal

🤝 Contributing

Contributions, issues and feature requests are welcome in both projects. Feel free to check the issues page and the contributing guide if you would like to contribute.

📝 License

Copyright (c) 2002-2022 Guardsquare NV. ProGuard is released under the GNU General Public License, version 2, with exceptions granted to a number of projects.