code: public static AndroidPublisher init( String applicationName,
              @Nullable String serviceAccountEmail ) throws IOException, GeneralSecurityException
      {
          Preconditions.checkArgument( !Strings.isNullOrEmpty( applicationName ),
                  "applicationName cannot be null or empty!" );
  
          // Authorization.
          newTrustedTransport();
          Credential credential;
          credential = authorizeWithServiceAccount( serviceAccountEmail );
  
          // Set up and return API client.
          return new AndroidPublisher.Builder(
                  httpTransport, JSON_FACTORY, credential ).setApplicationName( applicationName )
                  .build();
      }
docs: Performs all necessary setup steps for running requests against the API.
  
  @param applicationName the name of the application: com.example.app
  @param serviceAccountEmail the Service Account Email (empty if using
  installed application)
  @return the {@Link AndroidPublisher} service
  @throws GeneralSecurityException
  @throws IOException