Android Proguard - ClassNotFoundException

Question

I enabled proguard for my android app. I can build the project successfully but it crashes on startup with classNotFoundException. It doesn't even find the launcher activity. Here is my proguard rules file

-libraryjars libs

-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application

-keepnames class com.mypackage.** { *; } //someone suggested this but doesn't work

# We only want obfuscation
-keepattributes InnerClasses,Signature

# Sdk
-keep public interface com.zendesk.sdk.** { *; }
-keep public class com.zendesk.sdk.** { *; }

# Appcompat and support
-keep interface android.support.v7.** { *; }
-keep class android.support.v7.** { *; }
-keep interface android.support.v4.** { *; }
-keep class android.support.v4.** { *; }

# Gson
-keep interface com.google.gson.** { *; }
-keep class com.google.gson.** { *; }

# Retrofit
#-keep class com.google.inject.** { *; }
#-keep class org.apache.http.** { *; }
#-keep class org.apache.james.mime4j.** { *; }
#-keep class javax.inject.** { *; }
#-keep class retrofit.** { *; }
#-keep interface retrofit.** { *; }

# Retrofit
-keep class com.squareup.okhttp.** { *; }
-keep interface com.squareup.okhttp.** { *; }
-dontwarn com.squareup.okhttp.**

-dontwarn rx.**
-dontwarn retrofit.**
-dontwarn okio.**
-keep class retrofit.** { *; }
-keepclasseswithmembers class * {
    @retrofit.http.* <methods>;
}

# Jackson
-keepattributes *Annotation*,EnclosingMethod,Signature
-keepnames class com.fasterxml.jackson.** { *; }
 -dontwarn com.fasterxml.jackson.databind.**
 -keep class org.codehaus.** { *; }
 -keepclassmembers public final enum org.codehaus.jackson.annotate.JsonAutoDetect$Visibility {
 public static final org.codehaus.jackson.annotate.JsonAutoDetect$Visibility *; }
-keep public class your.class.** {
  public void set*(***);
  public *** get*();
}

#Picasso
-dontwarn com.squareup.okhttp.**

#-dontwarn javax.management.**
#-dontwarn java.lang.management.**
#-dontwarn org.apache.log4j.**
#-dontwarn org.apache.commons.logging.**
#-dontwarn org.json.*
#-dontwarn org.apache.commons.codec.binary.Base64

#-keep class javax.** {* ; }
#-keep class org.** { *; }

-dontwarn org.mortbay.**
-dontwarn org.slf4j.**
-dontwarn org.apache.log4j.**
-dontwarn org.apache.commons.logging.**
-dontwarn org.apache.commons.codec.binary.** 

and here is my build.gradle file if that helps but it doesn't include all the dependencies. I have some jars in the libs folder as well.

apply plugin: 'com.android.application'
apply plugin: 'robolectric'
apply plugin: 'android'
apply plugin: 'newrelic'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.2"

    defaultConfig {
        applicationId "com.mypackage"
        minSdkVersion 14
        targetSdkVersion 21
        versionCode 54
        versionName "2.002"
        multiDexEnabled true
        testInstrumentationRunner "com.google.android.apps.common.testing.testrunner.GoogleInstrumentationTestRunner"
        resConfigs "en", "fr" , "ar"
    }
    buildTypes {
        release {
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }

        debug {
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    sourceSets {
        androidTest {
            setRoot('src/test')
        }
    }

    dexOptions {
        javaMaxHeapSize "4g"
    }

    lintOptions {
        checkReleaseBuilds false
        // Or, if you prefer, you can continue to check for errors in release builds,
        // but continue the build even when errors are found:
        abortOnError false
    }

    repositories{
        maven { url 'https://zendesk.artifactoryonline.com/zendesk/repo' }
    }

    repositories {
        mavenCentral()
    }

    dependencies {
        compile fileTree(dir: 'libs', include: '*.jar')
        compile 'com.android.support:appcompat-v7:21.+'
        compile 'com.github.chrisbanes.photoview:library:1.2.3'
        compile 'com.etsy.android.grid:library:1.0.5'
        compile 'com.facebook.android:facebook-android-sdk:3.21.1'
        compile 'com.google.android.gms:play-services-base:6.5.+'
        compile 'com.google.android.gms:play-services-wallet:6.5.+'
        compile 'com.google.android.gms:play-services-ads:6.5.+'
        compile 'com.google.android.gms:play-services-maps:6.5.+'
        compile 'com.google.android.gms:play-services-drive:6.5.+'
        compile 'com.google.android.gms:play-services-appindexing:6.5.+'
        compile 'com.google.android.gms:play-services-location:6.5.+'
        compile 'com.google.android.gms:play-services-identity:6.5.+'
        compile 'com.google.android.gms:play-services-plus:6.5.+'
        compile 'com.android.support:multidex:1.0.+'
        compile project(':Adjust')
        compile project(':aFileChooser-cbccac1d1cb74a6d57d25c5ded61e4bf4fc40c91')
        compile 'com.parse.bolts:bolts-android:1.+'
        compile 'com.squareup.picasso:picasso:2.4.0'
        compile 'com.android.support:recyclerview-v7:+'
        compile (group: 'com.zendesk', name: 'sdk', version: '1.0.0.1'){
            //    exclude group:'picasso'
        }
        compile 'com.android.support:recyclerview-v7:+'
        compile 'com.newrelic.agent.android:android-agent:4.+'
        compile 'com.fasterxml.jackson.core:jackson-databind:2.4.2'
        compile 'com.fasterxml.jackson.core:jackson-annotations:2.4.2'
        compile 'com.fasterxml.jackson.core:jackson-core:2.4.2'


        /*compile ('oauth.signpost:signpost-commonshttp4:1.2.1.2') {
            exclude module: 'commons-logging'
            exclude module: 'httpcore'
            exclude module: 'httpclient'
        }
        compile ('oauth.signpost:signpost-core:1.2.1.2') {
            exclude module: 'commons-codec'
        }*/

        androidTestCompile 'org.robolectric:robolectric:2.4'
        androidTestCompile('junit:junit:4.12')
        androidTestCompile('org.mockito:mockito-core:1.10.19')

    }

    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/ASL2.0'
        exclude 'LICENSE.txt'
    }
}



robolectric {
    include '**/*Test.class'
}

Here is the full stack trace:

02-17 19:01:09.752: E/AndroidRuntime(2079): FATAL EXCEPTION: main
02-17 19:01:09.752: E/AndroidRuntime(2079): Process: com.mypackage, PID: 2079
02-17 19:01:09.752: E/AndroidRuntime(2079): java.lang.NoClassDefFoundError: Failed resolution of: Lcom/mypackage/activities/MainActivity;
02-17 19:01:09.752: E/AndroidRuntime(2079):     at cmypackage.application.ApplicationContextProvider.onCreate(Unknown Source)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1011)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4518)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.app.ActivityThread.access$1500(ActivityThread.java:144)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1339)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.os.Handler.dispatchMessage(Handler.java:102)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.os.Looper.loop(Looper.java:135)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at android.app.ActivityThread.main(ActivityThread.java:5221)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at java.lang.reflect.Method.invoke(Native Method)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at java.lang.reflect.Method.invoke(Method.java:372)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
02-17 19:01:09.752: E/AndroidRuntime(2079): Caused by: java.lang.ClassNotFoundException: Didn't find class "mypackage.activities.MainActivity" on path: DexPathList[[zip file "/data/app/mypackage-1/base.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
02-17 19:01:09.752: E/AndroidRuntime(2079):     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
02-17 19:01:09.752: E/AndroidRuntime(2079):     at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
02-17 19:01:09.752: E/AndroidRuntime(2079):     ... 12 more
02-17 19:01:09.752: E/AndroidRuntime(2079):     Suppressed: java.lang.NoClassDefFoundError: mypackage.activities.MainActivity
02-17 19:01:09.752: E/AndroidRuntime(2079):         at dalvik.system.DexFile.defineClassNative(Native Method)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at dalvik.system.DexFile.defineClass(DexFile.java:226)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at dalvik.system.DexPathList.findClass(DexPathList.java:321)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54)
02-17 19:01:09.752: E/AndroidRuntime(2079):         ... 14 more
02-17 19:01:09.752: E/AndroidRuntime(2079):     Suppressed: java.lang.ClassNotFoundException: mypackage.MainActivity
02-17 19:01:09.752: E/AndroidRuntime(2079):         at java.lang.Class.classForName(Native Method)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
02-17 19:01:09.752: E/AndroidRuntime(2079):         at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
02-17 19:01:09.752: E/AndroidRuntime(2079):         ... 13 more
02-17 19:01:09.752: E/AndroidRuntime(2079):     Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack available

Edit: Below is the missing part from the stacktrace.

02-17 19:01:09.749: I/MultiDex(2079): VM with version 2.1.0 has multidex support
02-17 19:01:09.749: I/MultiDex(2079): install
02-17 19:01:09.749: I/MultiDex(2079): VM has multidex support, MultiDex support library is disabled.
02-17 19:01:09.750: I/art(2079): Rejecting re-init on previously-failed class java.lang.Class<android.support.v4.app.FragmentActivity>
02-17 19:01:09.750: I/art(2079): Rejecting re-init on previously-failed class java.lang.Class<android.support.v4.app.FragmentActivity>
02-17 19:01:09.751: I/art(2079): Rejecting re-init on previously-failed class java.lang.Class<mypackage.activities.MainActivity>
02-17 19:01:09.751: I/art(2079): Rejecting re-init on previously-failed class java.lang.Class<mypackage.activities.MainActivity>
02-17 19:01:09.751: D/AndroidRuntime(2079): Shutting down VM
02-17 19:01:09.751: D/AndroidRuntime(2079): --------- beginning of crash

Furfural

Please add the complete stack trace from logcat. – Johnsonian

@Johnsonian posted the stack trace – Furfural

I guess everything works fine if you disable proguard right? – Ennead

exactly. and there is something i missed in the stack trace. I am editing the question to add that. It might give you a clue – Furfural

@Johnsonian edited my question. Please have a look. Thanks – Furfural

Answer 1

You'll want to also make sure to add in the New Relic proguard exceptions found here: https://docs.newrelic.com/docs/mobile-monitoring/mobile-monitoring-installation/android/installing-android-apps-gradle-android-studio#proguard

-keep class com.newrelic.** { *; }
-dontwarn com.newrelic.**
-keepattributes Exceptions, Signature, InnerClasses

Alroi

Thanks you so much. It worked :) but while trying it in Debug build. I have to build the project every time because the execution fails with :app:retraceDebugMainDexClassList FAILED Error:Execution failed for task ':app:retraceDebugMainDexClassList'. > unable to read mapping file. Any thoughts on this ? – Furfural

Using minifyEnabled true for debug builds isn't really doing you a lot of good. Does setting that to false for debug builds remove the error? – Alroi

I just wanted to test it on debug version. Thats fine now. but cant build with proguard-android-optimize.txt. it works with proguard-android.txt though – Furfural

Well, in your build.gradle you have specified proguard-android.txt and not proguard-android-optimize.txt for release and debug build types. That's probably why that doesn't work. – Alroi

I meant to say that when i change the above to optimize.txt, the build fails. – Furfural

Answer 2

I know this is a rather old post but I would like to highlight the following should it help someone in the future.

The ClassNotFoundException is an exception caused by applying name obfuscation to a class that's accessed using reflection. For example if ProGuard renames the class MyClass, which is accessed in the code like this: Class.forName("MyClass");, a ClassNotFoundException will be thrown if the string still refers to MyClass.

This is where we would need to add a -keep option in order for ProGuard to not rename that class;

-keep class com.example.MyClass

When using broad -keep options (ending with .** { *; }), you will instruct ProGuard not to shrink, optimize or obfuscate all classes and classmembers for the package name mentioned before the wildcards. This will eventually lead in a poorly optimized project. Therefore it's better to narrow down such -keep option to only target the missing class. In OP's example, the following error is thrown:

Caused by: java.lang.ClassNotFoundException: Didn't find class "mypackage.activities.MainActivity"

Adding a -keep option for the missing class like shown below will tackle this particular issue;

-keep class mypackage.activities.MainActivity

ProGuard can help you set up narrowed down -keep options if you add -addconfigurationdebugging to the configuration file, more details on this feature is documented in the ProGuard manual, here.

Recently the ProGuard Playground was released, you can quickly visualise the effect of the broad -keep options vs the narrowed down ones. A nice benefit here is that you do not need to continuously (re-)build the project.

Bewitch

Answer 3

Remove the obfuscation rules related to activity and all also related to support libaries.Android studio by default has those templates.You could enable them by adding this rule in your gradle

buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt')
        }
    }

Also please edit the rule for Jackson processor

-keep public class your.class.** {
  public void set*(***);
  public *** get*();
}

In this your class.** is the POJO(getter/setter) class that you have created for parsing your response

Bulrush

I removed the rules. and edited the Jackson processor but still the same problem. I added the class thats referencing the jackson library to the above statement but didnt help – Furfural

also about the buildType configurations. I am already doing that. I have added all the rules to proguard-android.txt file – Furfural

Thats right so why are you specifically adding android rules to your set of rules,remove them – Bulrush

yeah i have done that. Removed all the android related rules. but still getting the same problem. My concern is this line in the logcat : VM has multidex support, MultiDex support library is disabled. I think this is a multidex problem. I had the same classNotfound exception before enabling multidex. After properly enabling multidex, i got rid of it but now after enabling proguard, i am getting the same problem – Furfural