title: WSO2 : Can't build system service cdmf android agent
body: <p>When i try to build system service application, i get this :</p>
  
  <p>I use android studio 3.0.0</p>
  
  <p>SDK API-24</p>
  
  <p>Build tools 26.0.2</p>
  
  <p>i use this documentation : <a href="https://docs.wso2.com/display/IoTS300/Integrating+the+Android+System+Service+Application#IntegratingtheAndroidSystemServiceApplication-Operationssupportedviathesystemserviceapplication" rel="nofollow noreferrer">https://docs.wso2.com/display/IoTS300/Integrating+the+Android+System+Service+Application#IntegratingtheAndroidSystemServiceApplication-Operationssupportedviathesystemserviceapplication</a></p>
  
  <pre><code>Information:Gradle tasks [clean, :app:assembleDebug]
  C:\Users\xxx\Downloads\cdmf-agent-android-master\cdmf-agent-android-master      \system-service\app\src\main\java\org\wso2\iot\system\service\api\NetworkConnectedReceiver.java
  Error:(64, 28) error: cannot find symbol method getCurrentUser()
  Error:(65, 70) error: cannot find symbol method getCurrentUser()
  C:\Users\xxx\Downloads\cdmf-agent-android-master\cdmf-agent-android-master\system-service\app\src\main\java\org\wso2\iot\system\service\api\OTAServerManager.java
  Error:(21, 26) error: cannot find symbol class NonNull
  Error:(36, 18) error: cannot find symbol class SystemProperties
  Error:(278, 30) error: cannot find symbol class NonNull
  Error:(162, 41) error: cannot find symbol variable SystemProperties
  C:\Users\xxx\Downloads\cdmf-agent-android-master\cdmf-agent-android-master\system-service\app\src\main\java\org\wso2\iot\system\service\api\SettingsManager.java
  Error:(33, 42) error: cannot find symbol method setDeviceOwner(ComponentName)
  C:\Users\xxx\Downloads\cdmf-agent-android-master\cdmf-agent-android-master\system-service\app\src\main\java\org\wso2\iot\system\service\SystemService.java
  Error:(35, 18) error: cannot find symbol class SystemProperties
  Error:(426, 42) error: cannot find symbol method getLegacyExternalStorageDirectory()
  Error:(718, 21) error: cannot find symbol variable SystemProperties
  C:\Users\xxx\Downloads\cdmf-agent-android-master\cdmf-agent-android-master\system-service\app\src\main\java\org\wso2\iot\system\service\utils\AppUtils.java
  Error:(20, 19) error: cannot find symbol class PackageInstallObserver
  Error:(22, 26) error: cannot find symbol class IPackageDeleteObserver
  Error:(57, 9) error: cannot find symbol class PackageInstallObserver
  Error:(57, 47) error: cannot find symbol class PackageInstallObserver
  Error:(214, 9) error: cannot find symbol class IPackageDeleteObserver
  Error:(214, 47) error: cannot find symbol class IPackageDeleteObserver
  C:\Users\xxx\Downloads\cdmf-agent-android-master\cdmf-agent-android-master\system-service\app\src\main\java\org\wso2\iot\system\service\utils\CommonUtils.java
  Error:(53, 16) error: cannot find symbol method startServiceAsUser(Intent,UserHandle)
  Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
  &gt; Compilation failed; see the compiler error output for details.
  Information:BUILD FAILED in 7s
  Information:18 errors
  Information:0 warnings
  Information:See complete output in console
  </code></pre>
  
  <p>Note that in my sdk, i can see class NonNull and SystemProperties.</p>
  
  <p>Thanks for help.
  Regards.</p>