Not able to get Authorization code and Client Secret from TokenRequest

Question

I am trying to create a oauth provider and oauth client using nimbus.oauth2.sdk 10.13. This is the client side code. This sends a token request using the authorization code previously received.

// Initialize client information
ClientID clientId = new ClientID("12345");
Secret secret = new Secret("abcdef");
URI redirectURL = URI.create("http://localhost:8080/tokenResponse");
AuthorizationCode authCode = new AuthorizationCode("aaa");

// Create TokenRequest
TokenRequest tokenRequest = new TokenRequest(
                    redirectURL,
                    new ClientSecretPost(clientId, secret),
                    new AuthorizationCodeGrant(authCode, redirectURL)
            );

// Send HTTP request
HTTPResponse httpResponse = tokenRequest.toHTTPRequest().send();
String responseBody = httpResponse.getContent();

// Parse and handle the token response
net.minidev.json.JSONObject tokenJson = OAuthUtil.parseJSONresponse(responseBody);
TokenResponse response = TokenResponse.parse(tokenJson);

if (response instanceof AccessTokenResponse) {
    System.out.println(new JSONObject(responseBody).toString());

} else {
    try {
        throw new OAuthException("Error in receiving token: " + tokenJson.getAsString("error"), 3);
    } catch (OAuthException e) {
        throw new RuntimeException(e);
    }
}

The above if used with any other provider (eg, Google, fakebook) returns the correct response body.

The below is my server side code:

try {
    LOGGER.log(Level.INFO,request.getParameter("client_id"));
    LOGGER.log(Level.INFO,request.getParameter("authorization_details"));

    TokenRequest tokenRequest = TokenRequest.parse(ServletUtils.createHTTPRequest(request));

    if (tokenRequest.getClientID() != null) {
        LOGGER.log(Level.INFO, "Client ID: " + tokenRequest.getClientID().getValue());
    } else {
        LOGGER.log(Level.WARNING, "Client ID is null");
    }
} catch (ParseException e) {
    LOGGER.log(Level.WARNING, "Error parsing token request: " + e.getMessage());
}

Tokens tokens = new Tokens(new BearerAccessToken(), new RefreshToken());
AccessTokenResponse accessTokenResponse = new AccessTokenResponse(tokens);
response.getWriter().write(accessTokenResponse.toJSONObject().toJSONString());

In the server side, am trying to get the client ID and client secret, authorization code. When got from request.getParameter() I am getting the client ID. But the same cannot be received using tokenRequest.getClientID(). Why is that so?