"ClassCastException" being thrown on invoking a hosted webservice

My hosted web service is a very simple web service:
public class GetCurrentTimeService implements IBackendlessService {
public long getCurrentTimeinMillis(){
return System.currentTimeMillis();
But whenever i am trying to invoke it in my Android code: Backendless.CustomService.invoke(“GetCurrentTime”, “1.0”, “getCurrentTimeinMillis”, null); I am getting the following exception.
ExceptionClass:“ClassCastException” {Msg:“weborb.reader.StringType cannot be cast to weborb.reader.ArrayType”, Cause:“none”}
Am I invoking it wrong?

Please try code example added in InvocationExample class (it included into generated android sdk):

public class InvocationExample
    public static void main( String[] args )
        GetCurrentTimeService getCurrentTimeService = GetCurrentTimeService.getInstance();

        Object result = getCurrentTimeService.getCurrentTimeinMillis();
        System.out.println( result );

Android Studio is unable to find the GetCurrentTimeService class.
I included the generated SDK in the libs folder and synced the gradle files but it still failed to recognize the class.

I was able to call the function by including the java file in my code though.