title: java.util.zip.ZipException: duplicate entry support v4 PrintHelper$1.class
body: <p>I am not sure what this error means.</p>
  
  <pre><code>Error:Execution failed for task': eCampus :  packageAllDefaultFlavorDebugClassesForMultiDex'.
  &gt; java.util.zip.ZipException: duplicate entry: android/support/v4/print/PrintHelper$1.class
  </code></pre>
  
  <p>my bulid.gradle:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  android {
      compileSdkVersion 21
      buildToolsVersion '22.0.1'
      defaultConfig {
          applicationId "tw.edu.chu.ecampus"
          minSdkVersion 11
          targetSdkVersion 21
          multiDexEnabled true
      }
      buildTypes {
          release {
              minifyEnabled true
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
          }
      }
      dexOptions {
          preDexLibraries = false
      }
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_1_7
          targetCompatibility JavaVersion.VERSION_1_7
      }
  }
  repositories {
      mavenCentral()
  }
  dependencies {
      compile project(':G0.10.ABS')//ActionBarSherlock
      compile project(':vitamio')
      compile 'com.google.android.gms:play-services-maps:7.5.0'
      compile 'com.google.android.gms:play-services-gcm:7.5.0'
      compile 'com.android.support:multidex:1.0.1'
      androidTestCompile 'com.android.support:multidex-instrumentation:1.0.1'
  }
  </code></pre>
  
  <p>Error does not show up during gradle sync. Just when I try to run the application
  What could be the problem?</p>