Can a plain java code act as a OAuth 2.0 client and retrieve data

Question

We have a third part provider that hold our HR data (employee) and I need to retrieve employee data from their RESTful-based API that returns JSON-encoded responses and uses standard HTTP response codes, authentication, and verbs.

This service use OAuth2 protocol.

https://developer.employmenthero.com/api-references/#icon-book-open-introduction

My requirement is to update local database daily basis retrieving data from above service using a java code running in background

Can I consume Json data from a pure java code without a browser?

I'm not much familiar with OAuth2 and having issues with the redirect_url because it's just a java code. Implicit OAuth2 implementation is also an option for me. Is this something achievable?

Can someone provide me some guidelines please.

I have obtained client_id and the secret from this service.

My Sample code is like below..

 try {
            

    String clientId = "xxxxxxxxxx";
        String clientSecret = "xxxxxxxxxxxxxxxx";
        String tokenUrl = "https://oauth.employmenthero.com/oauth2/authorize";
        String scope = "read write"; // Optional scope

            // Create credentials string (Base64 encoded)
            String credentials = clientId + ":" + clientSecret;
            String encodedCredentials = Base64.getEncoder().encodeToString(credentials.getBytes());

            // Prepare POST data
            String postData = "grant_type=client_credentials";
            if (scope != null && !scope.isEmpty()) {
                postData += "&scope=" + scope;
            }

            // Create URL object with token endpoint
            URL url = new URL(tokenUrl);

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

            // Set the request method to POST
            connection.setRequestMethod("POST");

            // Set the Content-Type header
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            connection.setRequestProperty("Authorization", "Basic " + encodedCredentials);

            // Enable input/output
            connection.setDoOutput(true);

            // Write POST data to output stream
            connection.getOutputStream().write(postData.getBytes("UTF-8"));

            // Get response code
            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

            // Read response
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            StringBuilder response = new StringBuilder();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            // Print response
            System.out.println("Response: " + response.toString());

            // Close connection
            connection.disconnect();

   } catch (IOException e) {
            e.printStackTrace();
   }