title: Android aar dependencies
body: <p>I am new to Gradle build system, I have a library project which includes dependencies like Retrofit, okhttp etc. </p>
  
  <p>I compiled my project and created an aar file. I created a dummy project and added my library aar as a dependency. </p>
  
  <p>Now if I don't add Retrofit and okhttp as dependency in my dummy app's build.gradle file, my app crashes with class not found exception.</p>
  
  <p>My Question is : Since the library aar file already includes Retrofit and okhttp as dependency then why do I need to add them explicitly in dummy app's build.gradle file too? Is there a workaround.</p>
  
  <p>Here is my library build.gradle</p>
  
  <pre><code>    apply plugin: 'com.android.library'
      buildscript {
          repositories {
              mavenCentral()
              jcenter()
          }
      dependencies {
          classpath 'com.android.tools.build:gradle:1.0.+'
      }
  }
  allprojects {
      repositories {
          jcenter()
      }
  }
  android {
      compileSdkVersion 22
      buildToolsVersion "21.1.2"
  
      defaultConfig {
          minSdkVersion 14
          targetSdkVersion 22
          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-v7:22.+'
      compile 'com.android.support:recyclerview-v7:21.+'
      compile 'com.android.support:cardview-v7:21.+'
      compile 'com.google.android.gms:play-services:6.5.87'
      compile 'com.squareup.okhttp:okhttp:2.2.0'
      compile 'com.squareup.retrofit:retrofit:1.9.0'
      }
  </code></pre>