code: public static void closeAppOnPebble(final Context context, final UUID watchappUuid)
              throws IllegalArgumentException {
  
          if (watchappUuid == null) {
              throw new IllegalArgumentException("uuid cannot be null");
          }
  
          final Intent stopAppIntent = new Intent(INTENT_APP_STOP);
          stopAppIntent.putExtra(APP_UUID, watchappUuid);
          context.sendBroadcast(stopAppIntent);
      }
docs: Send a message to the connected Pebble to close an application identified by a UUID. If this application is not
  currently running, the message is ignored.
  
  @param context
  The context used to send the broadcast.
  @param watchappUuid
  A UUID uniquely identifying the target application. UUIDs for the stock kit applications are available in
  {@link Constants}.
  
  @throws IllegalArgumentException
  Thrown if the specified UUID is invalid.