title: Execution failed for task ':app:transformClassesWithDexForDebug' while implementing Google sign in for Android
body: <p>I'm trying to implement Google sign in for Android and I'm following the instructoins via</p>
  
  <p><a href="https://developers.google.com/identity/sign-in/android/start-integrating">https://developers.google.com/identity/sign-in/android/start-integrating</a></p>
  
  <p>But while building the application I'm receiving the following error.</p>
  
  <blockquote>
    <p>Information:Gradle tasks [:app:generateDebugSources,
    :app:generateDebugAndroidTestSources, :app:assembleDebug]
    :app:preBuild UP-TO-DATE :app:preDebugBuild UP-TO-DATE
    :app:checkDebugManifest :app:preReleaseBuild UP-TO-DATE
    :app:prepareComAndroidSupportAppcompatV72301Library UP-TO-DATE
    :app:prepareComAndroidSupportDesign2301Library UP-TO-DATE
    :app:prepareComAndroidSupportSupportV42301Library UP-TO-DATE
    :app:prepareComGoogleAndroidGmsPlayServicesAds810Library UP-TO-DATE
    :app:prepareComGoogleAndroidGmsPlayServicesAnalytics810Library
    UP-TO-DATE
    :app:prepareComGoogleAndroidGmsPlayServicesAppindexing810Library
    UP-TO-DATE :app:prepareComGoogleAndroidGmsPlayServicesBase810Library
    UP-TO-DATE
    :app:prepareComGoogleAndroidGmsPlayServicesBasement810Library
    UP-TO-DATE
    :app:prepareComGoogleAndroidGmsPlayServicesIdentity810Library
    UP-TO-DATE
    :app:prepareComGoogleAndroidGmsPlayServicesMeasurement810Library
    UP-TO-DATE :app:prepareComGoogleAndroidGmsPlayServicesPlus810Library
    UP-TO-DATE :app:prepareDebugDependencies :app:compileDebugAidl
    UP-TO-DATE :app:compileDebugRenderscript UP-TO-DATE
    :app:generateDebugBuildConfig UP-TO-DATE :app:generateDebugAssets
    UP-TO-DATE :app:mergeDebugAssets UP-TO-DATE
    :app:generateDebugResValues UP-TO-DATE :app:processDebugGoogleServices
    No matching client found for package name 'com.questo.rugved.questo'
    :app:generateDebugResources :app:mergeDebugResources UP-TO-DATE
    :app:processDebugManifest UP-TO-DATE :app:processDebugResources
    UP-TO-DATE :app:generateDebugSources UP-TO-DATE
    :app:preDebugAndroidTestBuild UP-TO-DATE
    :app:prepareDebugAndroidTestDependencies
    :app:compileDebugAndroidTestAidl UP-TO-DATE
    :app:processDebugAndroidTestManifest UP-TO-DATE
    :app:compileDebugAndroidTestRenderscript UP-TO-DATE
    :app:generateDebugAndroidTestBuildConfig UP-TO-DATE
    :app:generateDebugAndroidTestAssets UP-TO-DATE
    :app:mergeDebugAndroidTestAssets UP-TO-DATE
    :app:generateDebugAndroidTestResValues UP-TO-DATE
    :app:generateDebugAndroidTestResources UP-TO-DATE
    :app:mergeDebugAndroidTestResources UP-TO-DATE
    :app:processDebugAndroidTestResources UP-TO-DATE
    :app:generateDebugAndroidTestSources UP-TO-DATE
    :app:compileDebugJavaWithJavac UP-TO-DATE :app:compileDebugNdk
    UP-TO-DATE :app:compileDebugSources UP-TO-DATE
    :app:transformClassesAndResourcesWithExtractJarsForDebug
    :app:transformClassesWithDexForDebug UNEXPECTED TOP-LEVEL EXCEPTION:
    Error:Execution failed for task
    ':app:transformClassesWithDexForDebug'.
    com.android.build.transform.api.TransformException:
    com.android.ide.common.process.ProcessException:
    org.gradle.process.internal.ExecException: Process 'command
    '/usr/lib/jvm/java-7-oracle/bin/java'' finished with non-zero exit
    value 2 Information:BUILD FAILED Information:Total time: 1 mins 39.994
    secs Information:1 error Information:0 warnings Information:See
    complete output in console</p>
  </blockquote>
  
  <p>My top level gradle is </p>
  
  <pre>
  
      buildscript {
          repositories {
              jcenter()
          }
          dependencies {
              classpath 'com.android.tools.build:gradle:1.3.0'
              classpath 'com.google.gms:google-services:1.4.0-beta3'
  
              // NOTE: Do not place your application dependencies here; they belong
              // in the individual module build.gradle files
          }
      }
  
      allprojects {
          repositories {
              jcenter()
          }
      }
      </pre>
  
  <pre><code>My app level gradle is
  
  &lt;pre&gt;
  
      apply plugin: 'com.android.application'
      apply plugin: 'com.google.gms.google-services'
  
      android {
          compileSdkVersion 23
          buildToolsVersion '23.0.1'
  
          defaultConfig {
              applicationId "com.questo.rugved.questo"
              minSdkVersion 15
              targetSdkVersion 23
              versionCode 1
              versionName "1.0"
          }
          buildTypes {
              release {
                  minifyEnabled false
                  proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
              }
          }
      }
  
      dependencies {
          compile fileTree(dir: 'libs', include: ['*.jar'])
          compile 'com.android.support:appcompat-v7:23.0.1'
          compile 'com.android.support:design:23.+'
          compile 'com.google.android.gms:play-services-identity:8.1.0'
          compile 'com.google.android.gms:play-services-plus:8.1.0'
      }
  </code></pre>
  
  <p></p>
  
  <p>please help.</p>