`URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();

// optional default is GET
con.setRequestMethod("GET");

//add request header
con.setRequestProperty("Cache-Control", "no-cache");
con.setRequestProperty("Host", "www.example.com");
con.setRequestProperty("Upgrade", "websocket");
con.setRequestProperty("Connection", "upgrade");
con.setRequestProperty("Origin", "https://example.com");
con.setRequestProperty("Sec-WebSocket-Extensions", "x-webkit-deflate-frame");
con.setRequestProperty("Sec-WebSocket-Key", "QkWkChtTGpaZL5PkOMaRtg==");
con.setRequestProperty("Sec-WebSocket-Version", "13");
con.setRequestProperty("User-Agent", "Mozilla/..;

`Map<String, List<String>> headers = new HashMap<String, List<String>>();

headers.put("Connection", Arrays.asList("keep-alive", "Upgrade"));
headers.put("Sec-Websocket-Extensions", Arrays.asList("x-webkit-deflate-frame"));
headers.put("Sec-Websocket-key", Arrays.asList("cx36sHrtuW9HZAaB6kKa/Q=="));
headers.put("Sec-Websocket-Version", Arrays.asList("13"));
headers.put("Upgrade", Arrays.asList("websocket"));
headers.put("User-Agent", Arrays.asList("Mozill..."));

conf.beforeRequest(headers);

return config;`