I am begginer in Android App and using Java as when I add this code :

GCMRegistrar.checkDevice(this);
        GCMRegistrar.checkManifest(this);
        final String regId = GCMRegistrar.getRegistrationId(this);
        if (regId.equals("")) {
          GCMRegistrar.register(this, SENDER_ID);
        } else {
          Log.v(TAG, "Already registered");
        }

I had error on : SENDER_ID Log TAG

the error "cannot be resolved to available "