<a href="https://www.facebook.com/dialog/oauth?client_id=something&redirect_uri=http://our.domaine.register/postback?user_id=12345&scope=manage_pages&response_type=code">connect</a>

our.domaine.register/postback?user_id=12345&code=SoMEcOde

@RequestMapping(value = "/postback", params = "code", method = RequestMethod.GET)
@ResponseBody
private void accessCode(@RequestParam("code") String code,
                            HttpServletRequest request,
                            HttpServletResponse response) throws Exception {
        //Now the variable 'code' holds the authorization code
}

https://www.facebook.com/dialog/oauth?
    client_id=YOUR_APP_ID
   &redirect_uri=https://www.facebook.com/connect/login_success.html
   &response_type=token

public static Bundle decodeUrl(String s) {
        Bundle params = new Bundle();
        if (s != null) {
            String array[] = s.split("&");
            for (String parameter : array) {
                String v[] = parameter.split("=");
                // YG: in case param has no value
                if (v.length==2){
                    params.putString(URLDecoder.decode(v[0]),
                                 URLDecoder.decode(v[1]));
                }
                else {
                    params.putString(URLDecoder.decode(v[0])," ");
                }
            }
        }
        return params;
    }

    /**
     * Parse a URL query and fragment parameters into a key-value bundle.
     *
     * @param url the URL to parse
     * @return a dictionary bundle of keys and values
     */
    public static Bundle parseUrl(String url) {

        try {
            URL u = new URL(url);
            Bundle b = decodeUrl(u.getQuery());
            b.putAll(decodeUrl(u.getRef()));
            return b;
        } catch (MalformedURLException e) {
            Log.w(TAG, "parseUrl ex ->" + e.toString());
            return new Bundle();
        }
    }