Android: Duplicate class errors in proguard

Question

When compiling my app, I get the following error (sensitive pieces of path edited out)

Execution failed for task ':app:proguardDebug'.
> java.io.IOException: Can't write [/projects/app/build/intermediates/classes-proguard/debug/classes.jar] (Can't read [/.gradle/caches/modules-2/files-2.1/commons-codec/commons-codec/1.4/4216af16d38465bbab0f3dff8efa14204f7a399a/commons-codec-1.4.jar(;;;;;;!META-INF/MANIFEST.MF)] (Duplicate zip entry [commons-codec-1.4.jar:org/apache/commons/codec/binary/Base64.class]))

This indicates to me that the compiler sees two places where the app is trying to use commons.codec.binary.Base64.class as a dependency. I have checked and checked my libraries again, but only one library (Amazon AWS) is attempting to use it.

Above this error, I'm getting some other warnings which also raise a red flag for me:

Warning:can't write resource [META-INF/LICENSE.txt] (Duplicate zip entry [commons-lang3-3.1.jar:META-INF/LICENSE.txt])
Warning:can't write resource [META-INF/NOTICE.txt] (Duplicate zip entry [commons-lang3-3.1.jar:META-INF/NOTICE.txt])
Warning:can't write resource [META-INF/LICENSE.txt] (Duplicate zip entry [commons-codec-1.4.jar:META-INF/LICENSE.txt])
Warning:can't write resource [META-INF/NOTICE.txt] (Duplicate zip entry [commons-codec-1.4.jar:META-INF/NOTICE.txt])

I don't explicitly use commons-codec-1.4 or commons-lang3-3.1 in my app at all, thought I used to use lang3 before later removing it. Why are these being referenced in the compile log? Could one of my maven libraries be using them? I'll include a list of maven libraries below in my gradle file.

Here are my proguard and gradle files for reference:

PROGUARD

-keep class org.w3c.dom.bootstrap.** { *; }
-keep class org.joda.time.** { *; }
-keep class com.facebook.** { *; }
-keep class org.apache.commons.** { *; }
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable
-dontwarn org.codehaus.jackson.map.ext.**
-dontwarn oauth.**
-dontwarn com.amazonaws.**
-dontwarn org.joda.time.**
-dontwarn org.apache.commons.codec.**
-dontwarn com.fasterxml.jackson.databind.ext.**

GRADLE

apply plugin: 'com.android.application'

android {
    compileSdkVersion 20
    buildToolsVersion '20.0.0'

    defaultConfig {
        applicationId 'com.my.package'
        minSdkVersion 14
        targetSdkVersion 20
        versionCode 9
        versionName '1.2'
    }

    buildTypes {
        release {
            debuggable false
            runProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
        debug {
            debuggable true
            runProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
    }

    lintOptions {
        checkReleaseBuilds false
    }

    packagingOptions {
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/MANIFEST.MF'
    }
}

dependencies {
    compile fileTree(dir: 'libs',  include: ['*.jar'])

    //noinspection GradleDependency
    compile 'com.google.android.gms:play-services:5.0.89'

    compile 'com.nineoldandroids:library:2.4.0'
    compile 'com.viewpagerindicator:library:2.4.1@aar'
    compile 'se.emilsjolander:StickyScrollViewItems:1.1.0'
    compile 'se.emilsjolander:stickylistheaders:2.5.0'
    compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.2'
    compile project(':facebook')
    compile 'com.tumblr:jumblr:0.0.10'
    compile 'com.android.support:support-v4:20.0.0'
}

My best guess is one or more of those libraries is using apache lang3 and codec as dependencies of their own, which is resulting in a conflict when I compile the app. This problem only happens when I include Amazon as a required jar, so I know that is in some way acting as the culprit, but I don't know what else is conflicting with it.

I read something about using -injars with proguard, but according to their documentation Android shouldn't need you to use that.

Any advice would be greatly appreciated, thanks!

Answer 1

I am not sure if this will help you or not but I am posting my answer here in case others find this useful. My issue was that I had 2 references in my dependencies statement. I was using the Universal Image Loader library and my statement looked like this:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.1.1'
    compile 'com.android.support:support-v4:22.1.1'
    compile 'uk.co.chrisjenx:calligraphy:2.0.2'
    /* UIL was the failing reference */
    compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.3'
    compile 'com.google.android.gms:play-services:7.3.0'
}

The problem with this I realized (after a head smack moment) was that I had already referenced UIL via the libs folder (i.e. it was already being compiled by the statement compile fileTree(dir: 'libs', include: ['*.jar']). So it was compiling it once via libs and once via the explicit call to compile the reference to UIL. I removed the explicit call and that cleared up the error. Perhaps you are calling something in your libs directory that also contains a reference to the offending library then when it tries to compile the AWS Services it already has a version of the commons library and pukes.