buildscript {
  repositories {
    jcenter()
  }
  dependencies {
    classpath 'com.android.tools.build:gradle:2.1.3'
    classpath 'me.tatarka:gradle-retrolambda:3.2.5'
  }
}

apply plugin: 'me.tatarka.retrolambda'
...

android {
  ......  
  // 注释冲突
  packagingOptions {
     exclude 'META-INF/services/javax.annotation.processing.Processor'
  }
  // 使用Java1.8
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
  ......
}