Obfuscation (minifyEnabled true) not working in Debug and Release

Question

I cannot able to run apk using minifyEnabled true in Debug and Release mode.I have referred below links but none worked for me.

1.Android- Error:Execution failed for task ':app:transformClassesWithDexForRelease'

2.Error converting bytecode to dex: Cause: java.lang.RuntimeException: Exception parsing classes - Android studio 2.0 beta 6

Below is application build.gradle file

    apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"
    defaultConfig {
        applicationId 'XX.XX.XXX'
        minSdkVersion 21
        targetSdkVersion 23
        versionCode 9
        versionName "1.0"
        multiDexEnabled true
        vectorDrawables.useSupportLibrary = true



    }



    sourceSets.main {
        jni.srcDirs = [] //disable automatic ndk-build call
        jniLibs.srcDir 'src/main/libs' //integrate your libs from libs instead of jniLibs
    }
    dexOptions {
        javaMaxHeapSize "4g" //specify the heap size for the dex process
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'

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


    }
    productFlavors {
    }
    lintOptions {
        checkReleaseBuilds false
    }
    packagingOptions {
        exclude 'META-INF/LGPL2.1'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/LICENSE.txt'

    }
}



dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    //    compile files('libs/maflogonimo-1.210.3.jar')
    compile project(':android-logging-log4j-1.0.3')
    compile project(':log4j-1.2.17')
    compile files('libs/gson-2.6.2.jar')
    //compile files('libs/javarosa-libraries-2015-09-02.jar')
    compile 'com.android.support:design:23.4.0'
    //compile 'com.android.support:multidex:1.0.1'
    compile 'com.android.support:multidex:1.0.1'
    compile 'com.android.support:support-v4:23.4.0'
    compile 'com.android.support:cardview-v7:23.4.0'
    compile 'com.android.support:recyclerview-v7:23.4.0'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile 'com.google.android.gms:play-services-maps:10.0.1'
    compile 'com.google.android.gms:play-services-location:10.0.1'
    compile 'com.google.android.gms:play-services-auth:10.0.1'
    //    compile 'com.google.android.gms:play-services:10.0.1'

    //    compile 'com.google.android.gms:play-services-fcm:9.6.1'
    compile 'com.google.firebase:firebase-messaging:10.0.1'
    //    compile 'com.viewpagerindicator:library:2.4.1@aar'
    //compile files('libs/hellocharts-library-1.5.8.jar')
    compile 'com.esri.arcgis.android:arcgis-android:10.2.8-1'
    //GIS

    compile(name:'ClientHubSLL-3.16.1', ext:'aar')
    compile(name:'ClientLog-3.16.1', ext:'aar')
    compile(name:'Common-3.16.1', ext:'aar')
    compile(name:'Connectivity-3.16.1', ext:'aar')
    compile(name:'CoreServices-3.16.1', ext:'aar')
    compile(name:'DataVaultLib-3.16.1', ext:'aar')
    compile(name:'E2ETrace-3.16.1', ext:'aar')
    compile(name:'HttpConvAuthFlows-3.16.1', ext:'aar')
    compile(name:'HttpConversation-3.16.1', ext:'aar')
    compile(name:'MAFLogger-3.16.1', ext:'aar')
    compile(name:'MAFLogonCore-3.16.1', ext:'aar')
    compile(name:'ODataAPI-3.16.1', ext:'aar')
    compile(name:'ODataOnline-3.16.1', ext:'aar')
    compile(name:'Request-3.16.1', ext:'aar')
    compile(name:'SupportabilityFacade-3.16.1', ext:'aar')

    compile(name:'MAFCalendar-3.16.1', ext:'aar')
    compile(name:'MAFLocaleAwareControls-3.16.1', ext:'aar')
    compile(name:'MAFLogViewer-3.16.1', ext:'aar')
    compile(name:'MAFSettingScreen-3.16.1', ext:'aar')
    compile(name:'MAFTreeView-3.16.1', ext:'aar')
    compile(name:'MAFUIComponents-3.16.1', ext:'aar')
    compile(name:'XscriptParser-3.16.1', ext:'aar')
    compile(name:'MAFLogonUI-3.16.1', ext:'aar')
    compile(name:'MobilePlace-3.16.1', ext:'aar')

}

apply plugin: 'com.google.gms.google-services'

Below is proguard-rules.pro file

-renamesourcefileattribute SourceFile
-keepattributes SourceFile, LineNumberTable
-keepattributes Exceptions, Signature

-keepattributes EnclosingMethod
-keepattributes InnerClasses

-keep class org.javarosa.** { *; }
-keep class com.sap.** { *; }

-keep class jcifs.** { *; }


-dontwarn com.google.**
-dontwarn org.apache.**
-dontwarn com.sap.**
-dontwarn au.com.bytecode.**
-dontwarn org.joda.**
-dontwarn android.content.**
-dontwarn android.graphics.**
-dontwarn android.util.**
-dontwarn android.view.**

-dontwarn javax.servlet.**
-dontwarn jcifs.http.**
-dontwarn org.codehaus.**

Below exception while running from command line

cause: java.lang.RuntimeException: Exception parsing classes
    UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.RuntimeException: Exception parsing classes
        at com.android.dx.command.dexer.Main.processClass(Main.java:752)
        at com.android.dx.command.dexer.Main.processFileBytes(Main.java:718)
        at com.android.dx.command.dexer.Main.access$1200(Main.java:85)
        at com.android.dx.command.dexer.Main$FileBytesConsumer.processFileBytes(Main.java:1645)
        at com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:284)
        at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:166)
        at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:144)
        at com.android.dx.command.dexer.Main.processOne(Main.java:672)
        at com.android.dx.command.dexer.Main.processAllFiles(Main.java:574)
        at com.android.dx.command.dexer.Main.runMultiDex(Main.java:366)
        at com.android.dx.command.dexer.Main.run(Main.java:275)
        at com.android.dx.command.dexer.Main.main(Main.java:245)
        at com.android.dx.command.Main.main(Main.java:106)
Caused by: com.android.dx.cf.iface.ParseException: bad descriptor: charOffset
        at com.android.dx.cf.direct.AttributeListParser.parse(AttributeListParser.java:156)
        at com.android.dx.cf.direct.AttributeListParser.parseIfNecessary(AttributeListParser.java:115)
        at com.android.dx.cf.direct.AttributeListParser.getEndOffset(AttributeListParser.java:96)
        at com.android.dx.cf.direct.MemberListParser.parse(MemberListParser.java:213)
        at com.android.dx.cf.direct.MemberListParser.parseIfNecessary(MemberListParser.java:108)
        at com.android.dx.cf.direct.MethodListParser.getList(MethodListParser.java:54)
        at com.android.dx.cf.direct.DirectClassFile.parse0(DirectClassFile.java:542)
        at com.android.dx.cf.direct.DirectClassFile.parse(DirectClassFile.java:406)
        at com.android.dx.cf.direct.DirectClassFile.parseToInterfacesIfNecessary(DirectClassFile.java:388)
        at com.android.dx.cf.direct.DirectClassFile.getMagic(DirectClassFile.java:251)
        at com.android.dx.command.dexer.Main.parseClass(Main.java:764)
        at com.android.dx.command.dexer.Main.access$1500(Main.java:85)
        at com.android.dx.command.dexer.Main$ClassParserTask.call(Main.java:1684)
        at com.android.dx.command.dexer.Main.processClass(Main.java:749)
        ... 12 more
Caused by: java.lang.IllegalArgumentException: bad descriptor: charOffset
        at com.android.dx.rop.type.Type.intern(Type.java:330)
        at com.android.dx.cf.direct.AnnotationParser.parseAnnotation(AnnotationParser.java:248)
        at com.android.dx.cf.direct.AnnotationParser.parseAnnotations(AnnotationParser.java:223)
        at com.android.dx.cf.direct.AnnotationParser.parseAnnotationsList(AnnotationParser.java:188)
        at com.android.dx.cf.direct.AnnotationParser.parseParameterAttribute(AnnotationParser.java:127)
        at com.android.dx.cf.direct.StdAttributeFactory.runtimeVisibleParameterAnnotations(StdAttributeFactory.java:666)
        at com.android.dx.cf.direct.StdAttributeFactory.parse0(StdAttributeFactory.java:162)
        at com.android.dx.cf.direct.AttributeFactory.parse(AttributeFactory.java:96)
        at com.android.dx.cf.direct.AttributeListParser.parse(AttributeListParser.java:141)
        ... 25 more

16:35:57.798 [ERROR] [org.gradle.api.Project] 1 error; aborting
16:35:57.800 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Finished executing task ':app:transformClassesWithDexForRelease'
16:35:57.801 [LIFECYCLE] [class org.gradle.TaskExecutionLogger] :app:transformClassesWithDexForRelease FAILED
16:35:57.804 [INFO] [org.gradle.execution.taskgraph.AbstractTaskPlanExecutor] :app:transformClassesWithDexForRelease (Thread[Daemon worker,5,main]) completed. Took 1 mins 1.425 secs.
16:35:57.807 [DEBUG] [org.gradle.execution.taskgraph.AbstractTaskPlanExecutor] Task worker [Thread[Daemon worker,5,main]] finished, busy: 14 mins 11.51 secs, idle: 0.078 secs
16:35:57.870 [ERROR] [org.gradle.BuildExceptionReporter]
16:35:57.871 [ERROR] [org.gradle.BuildExceptionReporter] FAILURE: Build failed with an exception.
16:35:57.872 [ERROR] [org.gradle.BuildExceptionReporter]
16:35:57.872 [ERROR] [org.gradle.BuildExceptionReporter] * What went wrong:
16:35:57.872 [ERROR] [org.gradle.BuildExceptionReporter] Execution failed for task ':app:transformClassesWithDexForRelease'.
16:35:57.873 [ERROR] [org.gradle.BuildExceptionReporter] > com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'C:\Program Files\Java\jdk1.8.0_161\bin\java.exe'' finished with non-zero exit value 1
16:35:57.874 [ERROR] [org.gradle.BuildExceptionReporter]
16:35:57.875 [ERROR] [org.gradle.BuildExceptionReporter] * Try:
16:35:57.877 [ERROR] [org.gradle.BuildExceptionReporter] Run with --stacktrace option to get the stack trace.
16:35:57.878 [LIFECYCLE] [org.gradle.BuildResultLogger]
16:35:57.878 [LIFECYCLE] [org.gradle.BuildResultLogger] BUILD FAILED
16:35:57.880 [LIFECYCLE] [org.gradle.BuildResultLogger]
16:35:57.880 [LIFECYCLE] [org.gradle.BuildResultLogger] Total time: 14 mins 46.244 secs
16:35:57.930 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache fileHashes.bin (D:\myJobCard_SourceCode\.gradle\2.10\taskArtifacts\fileHashes.bin)
16:35:57.931 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache fileSnapshots.bin (D:\myJobCard_SourceCode\.gradle\2.10\taskArtifacts\fileSnapshots.bin)
16:35:57.932 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache taskArtifacts.bin (D:\myJobCard_SourceCode\.gradle\2.10\taskArtifacts\taskArtifacts.bin)
16:35:57.933 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache outputFileStates.bin (D:\myJobCard_SourceCode\.gradle\2.10\taskArtifacts\outputFileStates.bin)
16:35:57.933 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on task history cache (D:\myJobCard_SourceCode\.gradle\2.10\taskArtifacts).
16:35:57.935 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache jarSnapshots.bin (C:\Users\MY HOME\.gradle\caches\2.10\jarSnapshots\jarSnapshots.bin)
16:35:57.935 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on jar snapshots cache (C:\Users\MY HOME\.gradle\caches\2.10\jarSnapshots).
16:35:57.937 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache classAnalysis.bin (C:\Users\MY HOME\.gradle\caches\2.10\classAnalysis\classAnalysis.bin)
16:35:57.937 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on class analysis cache (C:\Users\MY HOME\.gradle\caches\2.10\classAnalysis).
16:35:57.939 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on cp_settings class cache for settings file 'D:\myJobCard_SourceCode\settings.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\settings_erwoxweslgmu8miqym6kcb1dt\cp_settings).
16:35:57.939 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on settings class cache for settings file 'D:\myJobCard_SourceCode\settings.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\settings_erwoxweslgmu8miqym6kcb1dt\settings).
16:35:57.940 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on cp_proj class cache for build file 'D:\myJobCard_SourceCode\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_7pkieelf3zpr7uf7k01l63rmx\cp_proj).
16:35:57.940 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on proj class cache for build file 'D:\myJobCard_SourceCode\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_7pkieelf3zpr7uf7k01l63rmx\proj).
16:35:57.940 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on cp_proj class cache for build file 'D:\myJobCard_SourceCode\android-logging-log4j-1.0.3\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_7utva779gtlkclvebpnh750jk\cp_proj).
16:35:57.941 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on proj class cache for build file 'D:\myJobCard_SourceCode\android-logging-log4j-1.0.3\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_7utva779gtlkclvebpnh750jk\proj).
16:35:57.941 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on cp_proj class cache for build file 'D:\myJobCard_SourceCode\app\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_56xn5xy2yld7cwkurxonzuovl\cp_proj).
16:35:57.942 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on proj class cache for build file 'D:\myJobCard_SourceCode\app\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_56xn5xy2yld7cwkurxonzuovl\proj).
16:35:57.942 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on cp_proj class cache for build file 'D:\myJobCard_SourceCode\log4j-1.2.17\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_8bsoptu904i00rpm86ii2r5ih\cp_proj).
16:35:57.942 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on proj class cache for build file 'D:\myJobCard_SourceCode\log4j-1.2.17\build.gradle' (C:\Users\MY HOME\.gradle\caches\2.10\scripts\build_8bsoptu904i00rpm86ii2r5ih\proj).
16:35:57.944 [DEBUG] [org.gradle.api.internal.artifacts.ivyservice.resolveengine.store.CachedStoreFactory] Resolution result cache closed. Cache reads: 0, disk reads: 0 (avg: 0.0 secs, total: 0.0 secs)
16:35:57.945 [DEBUG] [org.gradle.api.internal.artifacts.ivyservice.resolveengine.store.CachedStoreFactory] Resolution result cache closed. Cache reads: 0, disk reads: 8 (avg: 0.006 secs, total: 0.049 secs)
16:35:57.946 [DEBUG] [org.gradle.api.internal.artifacts.ivyservice.resolveengine.store.ResolutionResultsStoreFactory] Deleted 2 resolution results binary files in 0.003 secs
16:35:57.946 [DEBUG] [org.gradle.api.internal.artifacts.ivyservice.ivyresolve.memcache.InMemoryCachedRepositoryFactory]                                                                                                                        In-memory dependency metadata cache closed. Repos cached: 41, cache instances: 5, modules served from cache: 702, artifacts: 49
16:35:57.946 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache module-artifacts.bin (C:\Users\MY HOME\.gradle\caches\modules-2\metadata-2.16\module-artifacts.bin)
16:35:57.947 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache module-metadata.bin (C:\Users\MY HOME\.gradle\caches\modules-2\metadata-2.16\module-metadata.bin)
16:35:57.947 [DEBUG] [org.gradle.cache.internal.btree.BTreePersistentIndexedCache] Closing cache artifact-at-repository.bin (C:\Users\MY HOME\.gradle\caches\modules-2\metadata-2.16\artifact-at-repository.bin)
16:35:57.947 [DEBUG] [org.gradle.cache.internal.DefaultFileLockManager] Releasing lock on artifact cache (C:\Users\MY HOME\.gradle\caches\modules-2).
16:35:57.949 [DEBUG] [org.gradle.cache.internal.DefaultCacheAccess] Cache Plugin Resolution Cache (C:\Users\MY HOME\.gradle\caches\2.10\plugin-resolution) was closed 0 times.
16:35:57.950 [DEBUG] [org.gradle.api.internal.tasks.compile.daemon.CompilerDaemonManager] Stopping 0 compiler daemon(s).
16:35:57.950 [INFO] [org.gradle.api.internal.tasks.compile.daemon.CompilerDaemonManager] Stopped 0 compiler daemon(s).
16:35:57.952 [DEBUG] [org.gradle.launcher.daemon.server.exec.ExecuteBuild] The daemon has finished executing the build.
16:36:45.960 [DEBUG] [org.gradle.launcher.daemon.client.DaemonClientInputForwarder] Dispatching close input message: org.gradle.launcher.daemon.protocol.CloseInput@66269a8
16:36:45.966 [DEBUG] [org.gradle.launcher.daemon.client.DaemonClientConnection] thread 17: dispatching class org.gradle.launcher.daemon.protocol.CloseInput
16:36:45.971 [INFO] [org.gradle.launcher.daemon.client.DaemonClient] Received result Failure[value=org.gradle.initialization.ReportedException: org.gradle.internal.exceptions.LocationAwareException: Execution failed for task ':app:transformClassesWithDexForRelease'.] from daemon DaemonInfo{pid=22532, address=[dcdd43f4-9cff-4985-9851-6f1b9dfca80e port:65391, addresses:[/127.0.0.1, /0:0:0:0:0:0:0:1]], idle=false, context=DefaultDaemonContext[uid=b61dca0a-e70c-4dec-98ed-b69fe929e57e,javaHome=C:\Program Files\Java\jdk1.8.0_161,daemonRegistryDir=C:\Users\MY HOME\.gradle\daemon,pid=22532,idleTimeout=120000,daemonOpts=-Xmx4096m,-Dfile.encoding=windows-1252,-Duser.country=US,-Duser.language=en,-Duser.variant]} (build should be done).
16:36:45.977 [DEBUG] [org.gradle.launcher.daemon.client.DaemonClientConnection] thread 1: dispatching class org.gradle.launcher.daemon.protocol.Finished

I am using Android Studio 1.5.1.Is this Android studio version matters for obfuscation (minifyEnabled true) ? Are there any online or offline tools for encrypting the APK ? Please suggest me. I have wasted a lot of time on this. Please help me with this.Thanks in Advance.

Answer 1

Well... As you haven't mentioned yet, to the ant, to pro-guard your app, That's why it is not able to obfuscate it. Use explicitly useProguard true

---

Need a simple example of app gradle build file...? Find it below as it is of my project :

apply plugin: 'com.android.application'

android {
compileSdkVersion 26
defaultConfig {
    applicationId "com.xxxxxxxxxxcccccccvvvvvv.apps.firebase"
    minSdkVersion 16
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled true
        useProguard true
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        shrinkResources true
    }
}
}

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support:design:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.2'
implementation 'com.firebase:firebase-jobdispatcher:0.8.5'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

---

Now what it means in wording : It will only obfuscate your code in release of your project; which means you have to build your release apk.

How to test...? obfuscation happened or not?

Here we go...

1. Unzip apk file from linux or mac os terminal as: unzip apk_name
2. You will get your project files extracted... find dex file
3. Use dex2jar to convert it into jar
4. Read that jar file with JD-UI app
5. You will see all your java classes and core code files
6. Yes.... look neat.... Its a code.... But with obfuscation

Hmmmm... Hope it helps

Edit : 2

In the pro-guard rules files... Do not try to program it like code, just keep some classes which are not so important as : -keep public class OpenSource

Thats it.

Edit : 3

Most importantly you should and must as a beginner use default pro-guard file set by android studio or whichever your IDE; while creating the project. like :

proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

Edit : 4

It is a good habit to create a new sample project, learn how to implement any concept, once we are hands on it and cleared the concept..., Open the main project and implement it within..., As ... As of now , we are mastered the concept.

Edit : 5

It is always recommended to use Android Studio than any other IDE as it is officially by google as android is.. And it must be latest and updated IDE with minimum api 26 enabled. as google made compulsory last week that to upload apps on google play apps must target api level 26.

Also it helps to your project to get it build error free as all the latest dependencies are there along with patches.

Answer 2

1. Try to delete the .idea and .gradle directory under your project root directory and restart your Android Studio and re-sync your project. And change your build.gradle settings as below:

   android {
       ...
       compileSdkVersion 24
       buildToolsVersion "24.0.0"
   
       defaultConfig {
           ...
           targetSdkVersion 24 
           ...
       }
       ...
   }
   

2. Double check all the libraries inside libs to see if you have any duplicate ones with compile xxx, because you have below library dependencies declaration.

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

   This may cause the duplicate inclusion of libraries, for example, compile files('libs/gson-2.6.2.jar'). Try to remove all the duplicate libraries.

Answer 3

ever considered upgrading from Android Studio 1.5.1 to 3.1.3 ??

and I've double-checked, that this is not a question from a few years ago.

it reads bad descriptor: charOffset, which hints for errors in the build.gradle... most likely, that the referenced proguard-android-optimize.txt does not even exist within the file-system.

you'd have to reference the ProGuard configuration rules alike:

proguardFile "${project.rootDir}/proguard-rules.pro"
// proguardFile "${project.rootDir}/some-more-rules.pro"
shrinkResources true
minifyEnabled true