public void logout(String accessToken) {
        try {
            HttpClient hClient = new DefaultHttpClient();   
            HttpPost hPost = new HttpPost("https://authserver.mojang.com/logout");
            String jsonData = ""
                    + "{"
                    + "  \"accessToken\":\"" + accessToken + "\",\n"
                    + "  \"clientToken\":\"Atex\"\n"
                    + "}";
            hPost.setEntity(new StringEntity(jsonData, ContentType.create("application/json")));
            hClient.execute(hPost);
        } catch(IOException e) {
            e.printStackTrace();
        }
    }