Methods to handle social redirect when using popup for authorization with Apple SignIn with response type as form-post for a subdomain

SocialRedirect.java

/**
     * Redirect User to Social verify to complete social media authorization
     * 
     * @param state the state parameter containing BoxDomain for verification
     * @param code the authorization code
     * @param httpServletResponse the response with redirection for url
     *     
     * @throws IOException
     */
    @GetMapping(value = "/social-login/authorize")
    public void forwardSocialAuthorization(@RequestParam String state, @RequestParam Optional<String> code, HttpServletResponse httpServletResponse) throws IOException {
        String decodedStateParam = URLDecoder.decode(state, "UTF-8");
        JSONObject stateParams = new JSONObject(decodedStateParam);
        // your state param here, i added as just state
        String subDomain = stateParams.getString("subDomain");
        if(code.isPresent()){
            httpServletResponse.sendRedirect(redirectSocialVerifyUrl(subDomain, code.get()));
        }
    }

    /**
     * Url for redirecting user based on subdomain from where authorization is requested
     * 
     * @param subDomain the domain of the box
     * @param code the authorization code
     * @return the redirect to verfy social 
     */
    String redirectSocialVerifyUrlApple(String subDomain, String code, Optional<String> idToken, Optional<String> user) {
        String redirectUrl = "https://" + boxDomain + "/verify-social" + "?code=" + code;
        if (idToken.isPresent()) {
            redirectUrl = redirectUrl + "idToken=" + idToken.get();
        }
        if (user.isPresent()) {
            redirectUrl = redirectUrl + "user=" + user.get();
        }
        return redirectUrl;
    }