title: Android - duplicate entry: com/google/android/gms/internal/zzafz.class Error
body: <p>I got this error when I run the code -> </p>
  
  <pre><code>  Error:Execution failed for task ':app:transformClassesWithJarMergingForDebug'.&gt;
     com.android.build.api.transform.TransformException:   
      java.util.zip.ZipException: duplicate entry: 
       com/google/android/gms/internal/zzafz.class
  </code></pre>
  
  <p>I have no idea what does it means and do I fix it. I need your help guys
  I have treid several things but nothing really helped, I added "<code>multiDexEnabled true</code>" and that cause to that error.</p>
  
  <p>Before that error O had "<code>android error finished with non-zero exit value 2</code>". After I added "<code>multiDexEnabled true</code>", it gives me this error:</p>
  
  <p>"<code>duplicate entry: com/google/android/gms/internal/zzafz.class Error</code>"</p>
  
  <p>How can I fix it, any help would be appreciated!</p>
  
  <p><strong>this is my Manifest</strong></p>
  
  <pre><code>    apply plugin: 'com.android.application'
  
    android {
         compileSdkVersion 23
         buildToolsVersion "23.0.3"
  
  defaultConfig {
      applicationId "com.world.bolandian.gpstracker"
      minSdkVersion 14
      targetSdkVersion 23
      versionCode 1
      versionName "1.0"
      multiDexEnabled true
  }
  buildTypes {
      release {
          minifyEnabled false
          proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
      }
  }
  
  packagingOptions {
      exclude 'META-INF/LICENSE'
      exclude 'META-INF/LICENSE-FIREBASE.txt'
      exclude 'META-INF/NOTICE'
    }
  }
  
  dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     testCompile 'junit:junit:4.12'
     compile 'com.android.support:appcompat-v7:23.3.0'
     compile 'com.google.android.gms:play-services-maps:9.6.1'
     compile 'com.google.firebase:firebase-database:9.2.1'
     compile 'com.firebase:firebase-client-android:2.3.1'
     compile 'com.google.firebase:firebase-auth:9.2.1'
    }
     apply plugin: 'com.google.gms.google-services'
  </code></pre>