encoding Unicode (including emojis) for web server

NetworkTask.java

        String[] msg_chars = new String[msg_text.length()];

        for(int i=0; i < msg_text.length(); i++) {
            msg_chars[i] = "\\" +String.valueOf(String.format("\\u%04x", (int) msg_text.charAt(i)));
        }

        msg_text = ""
        for(int i=0; i < msg_chars.length; i++) {
            msg_text += msg_chars[i];
        }

        try {
            encoded_msg = URLEncoder.encode(msg_text, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }