Android: Issues enabling Java 8 features using a shared library.

I'm trying to take advantage of some Java 8 features to my Android project by following the documentation: https://developer.android.com/guide/platform/j8-jack.html

android {
  ...
  defaultConfig {
    ...
    jackOptions {
      enabled true
    }
  }
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

I'm using a shared library module. When I add jackOptions to my main module, it syncs and compiles with no issues. However, when the configuration is added to my serviceLibrary module, sync fails with: Error:Cannot add task ':serviceLibrary:assembleDebug' as a task with that name already exists.

My two build files are fairly similar in regards to the configuration:

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.1"

    defaultConfig {
        jackOptions {
            enabled true
        }
        applicationId "com.my.app"
        minSdkVersion 16
        targetSdkVersion 24
        versionCode 83
        versionName "2.0.8"
        vectorDrawables.useSupportLibrary = true

    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
...

so this error is not making a lot of sense to me. Any help would be appreciated.

Copyright Notice：Content Author:「jwBurnside」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/40901305/android-issues-enabling-java-8-features-using-a-shared-library