URL url = new URL(tokenUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");

conn.addRequestProperty("key", "value");

        try {
            URL  url = new URL(myUrl);

            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

            connection.setRequestMethod("POST");
            Map<String, String> params = new HashMap<>();
            params.put("grant_type", "password");
            params.put("username", myUserName);
            params.put("password", mtPassword);

            StringBuilder postData = new StringBuilder();
            for (Map.Entry<String, String> param : params.entrySet()) {
                if (postData.length() != 0) {
                    postData.append('&');
                }
                postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
                postData.append('=');
                postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
            }

            byte[] postDataBytes = postData.toString().getBytes("UTF-8");
            connection.setDoOutput(true);
            try (DataOutputStream writer = new DataOutputStream(connection.getOutputStream())) {
                writer.write(postDataBytes);
                writer.flush();
                writer.close();
                StringBuilder content;

                try (BufferedReader in = new BufferedReader(
                        new InputStreamReader(connection.getInputStream()))) {
                    String line;
                    content = new StringBuilder();
                    while ((line = in.readLine()) != null) {
                        content.append(line);
                        content.append(System.lineSeparator());
                    }
                }
                System.out.println(content.toString());
            } finally {
                connection.disconnect();
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

 try (DataOutputStream writer = new DataOutputStream(connection.getOutputStream())) {