String remoteAddr = req.getRemoteAddr();
ReCaptchaImpl reCaptcha = new ReCaptchaImpl();
reCaptcha.setPrivateKey("6LfUNtESAAAAANSiC1e3dD974bMUFY21S5QANakS");
String challenge = req.getParameter("recaptcha_challenge_field");
String uresponse = req.getParameter("recaptcha_response_field");
ReCaptchaResponse reCaptchaResponse = reCaptcha.checkAnswer(
remoteAddr, challenge, uresponse);
if (!reCaptchaResponse.isValid()) {
check.put("capcha", "Please enter exactly what you see.");
}