ProGuard - Application works fine in emulator, but fails when trying to build apk

Question

I'm trying to release my application, but I need the apk to be obfuscated + I'd like to cut some size. I also don't need the apk to be signed, so the debug build would do it.

I'm using a few Libraries:

• Guava 22.0
• Okhttp 3.8.1
• SimpleXML 2.7.+
• EventBus 3.0
• Apache Common Codec 1.10

The errors I currently get during apk build:

Warning:com.google.common.util.concurrent.FuturesGetChecked$GetCheckedTypeValidatorHolder$ClassValueValidator$1: can't find superclass or interface java.lang.ClassValue
Warning:com.google.common.util.concurrent.FuturesGetChecked$GetCheckedTypeValidatorHolder$ClassValueValidator: can't find referenced class java.lang.ClassValue
Warning:com.google.common.util.concurrent.FuturesGetChecked$GetCheckedTypeValidatorHolder$ClassValueValidator$1: can't find referenced class java.lang.ClassValue
Warning:there were 8 unresolved references to classes or interfaces.
Warning:Exception while processing task java.io.IOException: Please correct the above warnings first.
Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForDebug'.
> Job failed, see logs for details

Current proguard rules:

#EventBus
-keepclassmembers class ** {
    @org.greenrobot.eventbus.Subscribe <methods>;
}
-keep enum org.greenrobot.eventbus.ThreadMode { *; }

-printmapping out.map
-keepparameternames
-renamesourcefileattribute SourceFile
-keepattributes Exceptions,InnerClasses,Signature,Deprecated,SourceFile,LineNumberTable,EnclosingMethod

-keepattributes *Annotation*

-allowaccessmodification
-optimizationpasses 3

-keep public class * {
    public protected *;
}

-keepclassmembernames class * {
    java.lang.Class class$(java.lang.String);
    java.lang.Class class$(java.lang.String, boolean);
}

-keepclassmembernames class * {
    native <methods>;
}

-keepclassmembers class * extends java.lang.Enum {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

#SimpleXML
-dontwarn com.bea.xml.stream.**
-dontwarn org.simpleframework.xml.stream.**
-keep public class org.simpleframework.** { *; }
-keep class org.simpleframework.xml.** { *; }
-keep class org.simpleframework.xml.core.** { *; }
-keep class org.simpleframework.xml.util.** { *; }
-keepattributes ElementList, Root
-keepclassmembers,allowobfuscation class * {
    @org.simpleframework.xml.* <fields>;
    @org.simpleframework.xml.* <init>(...);
}
-keepclassmembers class * {
    @org.simpleframework.xml.* *;
}


#guava
-dontwarn com.google.errorprone.annotations.CanIgnoreReturnValue
-dontwarn com.google.errorprone.annotations.concurrent.LazyInit
-dontwarn com.google.errorprone.annotations.ForOverride
-dontwarn com.google.errorprone.annotations.IncompatibleModifiers
-dontwarn com.google.errorprone.annotations.RequiredModifiers
-dontwarn com.google.errorprone.annotations.Var
-dontwarn javax.inject.**
-dontwarn sun.misc.Unsafe
-dontwarn com.google.common.util.concurrent.**

#okhttp3
-dontwarn okio.**
-dontwarn javax.annotation.Nullable
-dontwarn javax.annotation.ParametersAreNonnullByDefault

build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.0"
    defaultConfig {
        applicationId "xxx"
        minSdkVersion 21
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
        debug {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    implementation 'com.android.support:appcompat-v7:26.0.0'
    implementation 'com.android.support:cardview-v7:26.0.0'
    implementation 'com.android.support:design:26.0.0'

    implementation 'org.greenrobot:eventbus:3.0.0'

    implementation('org.simpleframework:simple-xml:2.7.+') {
        exclude module: 'stax'
        exclude module: 'stax-api'
        exclude module: 'xpp3'
    }

    implementation 'com.squareup.okhttp3:okhttp:3.8.1'

    implementation group: 'commons-codec', name: 'commons-codec', version: '1.10'
    implementation 'com.google.guava:guava:22.0-android'
    androidTestCompile 'com.google.guava:guava:22.0-android'
    testImplementation 'junit:junit:4.12'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:support-v4:26.0.0'
}


configurations.all {
    resolutionStrategy.force 'com.google.code.findbugs:jsr305:1.3.9'
}

Putting -dontwarn javax.xml.stream.events.** reduces the warnings down to 86, but I'm not really sure how to tackle the rest of them.

Also, the line "Execution failed for task ':app:transformClassesAndResourcesWithProguardForDebug'. Is this error because of the warnings, or is it something completely different?

I'd really appreciate any help on this!

cheers

Update: Reduced the warnings to only 8, updated my proguard rules aswell as the warnings

Update2: Got rid of all the warnings, but the apk isn't obfuscated at all, i can simply decompile it with apktool/dex2jar and see everything thats going on.

Answer 1

Here the proguard rules that can help you:

# EventBus 3.0 rules
# http://greenrobot.org/eventbus/documentation/proguard/
-keepattributes *Annotation*
-keepclassmembers class ** {
    @org.greenrobot.eventbus.Subscribe <methods>;
}
-keep enum org.greenrobot.eventbus.ThreadMode { *; }

# Only required if you use AsyncExecutor
-keepclassmembers class * extends org.greenrobot.eventbus.util.ThrowableFailureEvent {
    <init>(java.lang.Throwable);
}

# SimpleXML proguard
# Keep public classes and methods.
-dontwarn com.bea.xml.stream.**
-dontwarn org.simpleframework.xml.stream.**
-keep class org.simpleframework.xml.**{ *; }
-keepclassmembers,allowobfuscation class * {
    @org.simpleframework.xml.* <fields>;
    @org.simpleframework.xml.* <init>(...);
}

#okhttp3 rules, https://github.com/square/okhttp#proguard
-dontwarn okio.**
-dontwarn javax.annotation.Nullable
-dontwarn javax.annotation.ParametersAreNonnullByDefault

For the old version of Guava :

# Configuration for Guava 18.0
#
# disagrees with instructions provided by Guava project: https://code.google.com/p/guava-libraries/wiki/UsingProGuardWithGuava

-keep class com.google.common.io.Resources {
    public static <methods>;
}
-keep class com.google.common.collect.Lists {
    public static ** reverse(**);
}
-keep class com.google.common.base.Charsets {
    public static <fields>;
}

-keep class com.google.common.base.Joiner {
    public static com.google.common.base.Joiner on(java.lang.String);
    public ** join(...);
}

-keep class com.google.common.collect.MapMakerInternalMap$ReferenceEntry
-keep class com.google.common.cache.LocalCache$ReferenceEntry

# http://stackoverflow.com/questions/9120338/proguard-configuration-for-guava-with-obfuscation-and-optimization
-dontwarn javax.annotation.**
-dontwarn javax.inject.**
-dontwarn sun.misc.Unsafe

# Guava 19.0
-dontwarn java.lang.ClassValue
-dontwarn com.google.j2objc.annotations.Weak
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement

Answer 2

I've just got the same error you did, and I solved it by adding a direct dontwar for java.lang:

-dontwarn java.lang.**

It went from 8 warnings to 0 and correct building of the APK.