# Can't get rid of Kotlin Metadata inside Android library project **URL:** \ **Category:** Android\ **Created:** [October 13, 2017, 4:17pm UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984 "2017-10-13T16:17:25Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![alex.gianq](https://avatars.discourse-cdn.com/v4/letter/a/aca169/32.png) [@alex.gianq](https://discuss.kotlinlang.org/u/alex.gianq)\ **Post date:** [October 13, 2017, 4:17pm UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984/1 "2017-10-13T16:17:25Z")
Hi there ! I’m having an issue that I did not manage to solve with Google (they do not give me an anwser : [Google Issue Tracker](https://issuetracker.google.com/issues/65623846) ) The issue is strongly linked to the Kotlin Android gradle plugin, and probably the way that it configures proguard, but I think you guys may have a solution for me (or I wish you do). I’m developing a SDK (Android library) in kotlin, and I have to obfuscate a large part of my code so the customer may not try and play with internal code. This is a requirement from my customer. My lib is coded in kotlin, and I used proguard through the gradle wrapper. Problem is that there are still @kotlin.Metadata (runtime) annotations inside the code after compile and obfuscation. With those annotations, it’s really easy to retrieve the java code that originated this bytecode (or at least method names, parameters, attributes, …). I first thought it was my fault, and my project had too many entropy sources that might have induced this behaviour, so I made a sample project to prove that the problem does not come from my sdk implementation. I created a new project with AS, then a lib module with 2 files : - facade.kt is my facade class, the one that I do not wish to obfuscate, so the customer may use it : - and in this sample, internal.kt holds the classes that I want to obfuscate : The proguard rules are injected into gradle project with this release closure : ``` buildTypes { release { minifyEnabled true proguardFiles 'proguard-rules.pro' } } ``` And here is `proguard-rules.pro` (only one line, nothing more) : ``` -keep class com.example.mylibrary.MyFacade {*;} ``` The result : when I `./gradlew clean myLib:assembleRelease`, I do obtain an aar in which my facade is kept, and my internal class has been renamed in ‘a’, with one method ‘a’, except that the class is still annotated with kotlin @Metadata, which holds every information that helps the decompiler retrieve the original class name, the method, attribute and argument names, etc… So my code is not so obfuscated at all… ``` @Metadata( mv = {1, 1, 7}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u001a\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0002\b\u0002\n\u0002\u0010\u0002\n\u0000\n\u0002\u0010\b\n\u0002\b\u0002\u0018\u00002\u00020\u0001B\u0005¢\u0006\u0002\u0010\u0002J\u0016\u0010\u0003\u001a\u00020\u00042\u0006\u0010\u0005\u001a\u00020\u00062\u0006\u0010\u0007\u001a\u00020\u0006¨\u0006\b"}, d2 = {"Lcom/example/mylibrary/InternalClass;", "", "()V", "doSomething", "", "firstArgument", "", "secondArgument", "mylibrary_release"} ) public final class a { ... } ``` So my question : is it possible to get rid of those annotations, am I the only one facing this problem, or have I missed something ? ---
**Author:** ![Quinlanzhong](https://avatars.discourse-cdn.com/v4/letter/q/5e9695/32.png) [@Quinlanzhong](https://discuss.kotlinlang.org/u/Quinlanzhong)\ **Post date:** [December 6, 2018, 7:11am UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984/2 "2018-12-06T07:11:12Z")
I am trying to get rid of those annotations too. In my project, all Kotlin Classes are filled in main dex, when I am using kotlin + multidex. MetaData runtime annotation is the main reason for my problems. Checkout this reply from google [Google Issue Tracker](https://issuetracker.google.com/issues/67553803) ---
**Author:** ![Quinlanzhong](https://avatars.discourse-cdn.com/v4/letter/q/5e9695/32.png) [@Quinlanzhong](https://discuss.kotlinlang.org/u/Quinlanzhong)\ **Post date:** [December 6, 2018, 7:11am UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984/3 "2018-12-06T07:11:49Z")
is it possible to get rid of those annotations? ---
**Author:** ![pdvrieze](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/pdvrieze/32/1882_2.png) [@pdvrieze](https://discuss.kotlinlang.org/u/pdvrieze)\ **Post date:** [December 7, 2018, 10:17pm UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984/4 "2018-12-07T22:17:44Z")
It should be possible using proguard (and the new Android stripper that should be compatiable with proguard). It does however mean that Kotlin reflection no longer works (Java reflection is fine, but meaningless if obfuscated). ---
**Author:** ![Quinlanzhong](https://avatars.discourse-cdn.com/v4/letter/q/5e9695/32.png) [@Quinlanzhong](https://discuss.kotlinlang.org/u/Quinlanzhong)\ **Post date:** [December 14, 2018, 9:52pm UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984/5 "2018-12-14T21:52:56Z")
I have tried it. It didn’t work. With proguard config `-whyyoukeeping`, it just explained it was a config direct keep it. I think that’ because of something `kotlin-android` gradle plugin do ---
**Author:** ![mgadzio](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/mgadzio/32/6433_2.png) [@mgadzio](https://discuss.kotlinlang.org/u/mgadzio)\ **Post date:** [June 10, 2019, 7:06pm UTC](https://discuss.kotlinlang.org/t/cant-get-rid-of-kotlin-metadata-inside-android-library-project/4984/6 "2019-06-10T19:06:20Z")
Any news in subject? Is there a way to remove @Metadata annotation?