'META-INF/version duplicate error when using Proguard

Gradle : 4.10.1 Gradle Android Plugin version : 3.3.2 Proguard : 6.0.3 JDK - 1.9 Android Studio 3.3.2 When I try to build apk release version along with Proguard. I get the following error -

Caused by: java.io.IOException: Please correct the above warnings first.
    at proguard.InputReader.execute(InputReader.java:149)
    at proguard.ProGuard.readInput(ProGuard.java:255)
    at proguard.ProGuard.execute(ProGuard.java:96)
    ......

This seems to be caused due to this -

Warning: class [META-INF/versions/9/module-info.class] unexpectedly contains class [module-info]
Note: duplicate definition of program class [module-info]
Note: there were 20 duplicate class definitions.
      (http://proguard.sourceforge.net/manual/troubleshooting.html#duplicateclass)
Warning: there were 21 classes in incorrectly named files.
         You should make sure all file names correspond to their class names.
         The directory hierarchies must correspond to the package hierarchies.

From extensive searching it looks like Proguard has a problem with META-INF/versions/9. I have multiple dependencies that contain this.

While the issue to seems to somewhat documented, no solutions prescribed seem to work. https://sourceforge.net/p/proguard/bugs/665/ suggests filtering out those class files via -

-injars my_lib.jar(!META-INF/versions/**.class)

However when I try this it just labels more files as duplicate and incorrectly named. I also tried excluding it via gradle-

packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/DEPENDENCIES.txt'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/license.txt'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/notice.txt'
        exclude 'META-INF/INDEX.LIST'
        exclude 'META-INF/versions'
        exclude 'META-INF/versions/9/module-info.class'
   }

This also fails to resolve the problem. How do I solve this problem ?

Solution 1:^[1]

I realise this is a very old question, but I was able to get this to work using this gradle configuration:

task obfuscate(type: proguard.gradle.ProGuardTask) {
    configuration files("proguard-project.txt")
    libraryjars files("build/rt.jar", "build/jce.jar")
    injars files("build/libs/desktop-${version}.jar"), filter: "!META-INF/versions/**/*.class"
    outjars files("build/libs/obfuscated.jar")
}

I think the issue with the injars directive you used might be the path - should be META-INF/versions/**/*.class.

Solution 2:^[2]

Using the option -ignorewarnings in proguard-project.txt 'fixed' it for me, the generated jar works fine as long as the only warnings mentioned by Proguard are related to META-INF.

Solution 3:^[3]

I realise this is an old question, but I had issues with this when upgrading some other libs in an application.

I found the <inLibsFilter> tag at the proguard maven plugin page which helped me get it to work. I used it like this (in my <configuration> tag:

            <inLibsFilter>!META-INF/versions/**</inLibsFilter>

Hopefully it can help others that may stumble upon it..

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Joel Auterson
Solution 2	Johan Stolk
Solution 3	anton_w

'META-INF/version duplicate error when using Proguard

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]

Sources

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