{

    client_id : 'Id_of_your_client',

    username : 'your_username',
    password : '@#$%^&',
    grant_type : "password"

}

{

    client_id : 'Id_of_your_client',

   // client_secret : 'optional depending on the type of client',

    grant_type : "refresh_token" ,

    refresh_token : refresh_token_you_got_earlier

}

headers :{

  Authorization : 'Bearer ' +  access_token_you_got

}

String uri = "http://localhost:7080/auth/realms/{RealmName}/protocol/openid-connect/token";

            HttpClient client = HttpClientBuilder.create().build();
            HttpPost post = new HttpPost(uri);
            post.setHeader("User-Agent",
                    "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36");
            List<BasicNameValuePair> urlParameters = new ArrayList<BasicNameValuePair>();
            urlParameters.add(new BasicNameValuePair("grant_type", "password"));
            urlParameters.add(new BasicNameValuePair("client_id", {ClientName}));
            urlParameters.add(new BasicNameValuePair("username", {UserName}));
            urlParameters.add(new BasicNameValuePair("password", {Password}));
            post.setEntity(new UrlEncodedFormEntity(urlParameters));
            HttpResponse response = client.execute(post);
            System.out.println("Response Code : " + response.getStatusLine().getStatusCode());
            BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer result = new StringBuffer();
            String line1 = "";
            while ((line1 = rd.readLine()) != null) {
                result.append(line1);
            }
            System.out.println(result);