@Override
 public String activateUser(final String email, final String otp) {
   try {
     final UserOtp userOtp = this.userOtpRepository.findUserOtpByUserNameAndOtp(email, otp);
     if (null == userOtp) {
       return null;
       // throw new ResourceNotFoundException(
       //		"error.entity.user.found", "User with given details does not exist");
     }
     final User user = userOtp.getThisUser();
     user.activate();
     this.userRepository.saveAndFlush(user);
     // after successful activation delete otp
     this.userOtpRepository.delete(userOtp);
     return userOtp.getReturnUrl();
   } catch (Exception e) {
     e.printStackTrace();
     return null;
   }
 }