SuccessListener.java

public class SuccessListener implements OnSuccessListener<SafetyNetApi.RecaptchaTokenResponse> {

        @Override
        public void onSuccess(final SafetyNetApi.RecaptchaTokenResponse recaptchaTokenResponse) {

            String userResponseToken = recaptchaTokenResponse.getTokenResult();
          
            if (!userResponseToken.isEmpty()) {
                RecaptchaResponseViewModel mViewModel = ViewModelProviders.of(MainActivity.this).get(RecaptchaResponseViewModel.class);
                mViewModel.getmRecaptchaObservable("https://www.google.com", userResponseToken, **SECRET KEY GOES HERE**).observe(MainActivity.this, new Observer<RecaptchaVerifyResponse>() {
                    @Override
                    public void onChanged(@Nullable RecaptchaVerifyResponse recaptchaVerifyResponse) {
                        if (recaptchaVerifyResponse != null && recaptchaVerifyResponse.isSuccess()) {
                            // User is a human. Congratulations!
                        } else {
                            // Response validation failed. Handle scenario
                        }
                    }
                });
            } else {
                // Device side validation resulted in no token. Failure
            }
        }
}