I am trying to create a folder from Java rest API on sharepoint

I am trying to create a folder using the access token I am getting the access but in the end, getting the response code 404. I have tried to develop a JsonInputString and then state the connection I have set values in httpconn and then tried to call the connection what am I doing wrong, It is working if I am hardcoding the values but not when I am dynamically getting it.

here is my code

    String siteURL, String folder) throws IOException {
        String wsURL = siteURL + "/_api/web/folders";
        URL url = new URL(wsURL);
        URLConnection connection = url.openConnection();
        String[] arr = siteURL.split("com");
        String siteNameURL = arr[arr.length-1];
        String jsonInputString = "{'__metadata': { 'type': 'SP.Folder' }, 'ServerRelativeUrl': '/sites"+ siteNameURL +"/Shared%20Documents/"
                + folder + "'}";
        HttpURLConnection httpConn = (HttpURLConnection) connection;
        try {
            clientID = sharePointclientID;
            clientSecret = secretKey;

            // AccessToken url : app.properties

            accessTokenScr = getSharepointTokenScripting();
            // Set header
            httpConn.setRequestProperty("Content-Type", "application/json;odata=verbose");
            httpConn.setRequestProperty("Accept", "application/json;odata=verbose");
            httpConn.setRequestProperty("Authorization", "Bearer " + accessTokenScr);
            httpConn.setDoOutput(true);
            httpConn.setDoInput(true);
            httpConn.setRequestMethod("POST");
            httpConn.setRequestProperty("X-RequestDigest", "SHAREPOINT_FORM_DIGEST");
            httpConn.setRequestProperty("Content-Length", Integer.toString(jsonInputString.getBytes("utf-8").length));
            DataOutputStream wr = new DataOutputStream(httpConn.getOutputStream());

            byte[] input = jsonInputString.getBytes("utf-8");
            wr.write(input, 0, input.length);

            String responseStr = "";
            if (httpConn.getResponseCode() == 201) {
                responseStr = "Folder has been created successfully. ResponseCode: " + httpConn.getResponseCode();
            } else {
                responseStr += "Error while creating folder, ResponseCode: " + httpConn.getResponseCode() + " "
                        + httpConn.getResponseMessage();
            }
            LOG.info(responseStr);