import com.google.api.client.http.HttpRequestFactory;
import com.google.api.client.http.HttpResponseException;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson.JacksonFactory;
import com.google.api.client.util.DateTime;
//import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.model.Calendar;
import com.google.api.services.calendar.model.Event;
import com.google.api.services.calendar.model.EventAttendee;
import com.google.api.services.calendar.model.EventDateTime;
import com.google.api.client.googleapis.services.GoogleClient.Builder;
//import com.google.api.services.calendar.Calendar.Calendars;
//import com.google.api.services.calendar.Calendar.Calendars.Insert;
import com.google.api.client.auth.oauth2.AuthorizationCodeFlow;
import com.google.api.client.auth.oauth2.draft10.AccessProtectedResource.Method;
import com.google.api.client.auth.oauth2.draft10.AccessTokenErrorResponse;
import com.google.api.client.auth.oauth2.draft10.AccessTokenResponse;
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.auth.oauth2.draft10.GoogleAccessTokenRequest.GoogleAuthorizationCodeGrant;
import com.google.api.client.googleapis.auth.oauth2.draft10.GoogleAccessProtectedResource;
import com.google.api.client.googleapis.auth.oauth2.draft10.GoogleAuthorizationRequestUrl;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Arrays;

@SuppressWarnings({ "deprecation", "unused" })
public class connect{

    public void setUp() throws IOException {

        HttpTransport httpTransport = new NetHttpTransport();
        JacksonFactory jsonFactory = new JacksonFactory();

        // The clientId and clientSecret are copied from the API Access tab on
        // the Google APIs Console
        String clientId = "MYCLIENTID";
        String clientSecret = "CLIENTSECRET";

        // Or your redirect URL for web based applications.
        String redirectUrl = "urn:ietf:wg:oauth:2.0:oob";
        String scope = "https://www.googleapis.com/auth/calendar";

        // Step 1: Autorizzazione -->
        String authorizationUrl = new GoogleAuthorizationRequestUrl(clientId, redirectUrl, scope)
            .build();

        // Point or redirect your user to the authorizationUrl.
        System.out.println("Vai al seguente indirizzo nel browser:");
        System.out.println(authorizationUrl);

        // Read the authorization code from the standard input stream.
        System.out.println("Qual e' il tuo codice di autorizzazione?");
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String code = in.readLine();

        // Fine Step 1 <--
        // Step 2: Scambio -->
        AccessTokenResponse authResponse = new GoogleAuthorizationCodeGrant(httpTransport, jsonFactory,
                clientId, clientSecret, code, redirectUrl).execute();
        System.out.println("Scrivi: "+authResponse);
        System.out.println("Token d'accesso: "+authResponse.accessToken);
        if(scope == "https://www.googleapis.com/auth/calendar")
        System.out.println("Scope di lettura e scrittura usato :"+scope);
        else
            System.out.println("Scope di sola lettura usato :"+scope);
        // Fine Step 2 <--

        GoogleAccessProtectedResource accessProtectedResource = new GoogleAccessProtectedResource(
                authResponse.accessToken, httpTransport, jsonFactory, clientId, clientSecret,
                authResponse.refreshToken);
        System.out.println("Il Client ID utilizzato e': "+accessProtectedResource.getClientId());
        System.out.println("Il Secret ID utilizzato e': "+accessProtectedResource.getClientSecret());
        System.out.println("L'url di autenticazione e': "+accessProtectedResource.getAuthorizationServerUrl());

        com.google.api.services.calendar.Calendar service = new com.google.api.services.calendar.Calendar(httpTransport, jsonFactory);
        Calendar cale = new Calendar();

        System.out.println("Menu'");
        System.out.println("Cosa desideri fare?");
        System.out.println("1) Creare un calendario");
        System.out.println("2) Creare un evento");
        System.out.println("3) Eliminare un calendario");
        System.out.println("0) Uscita");

        int scelta = Integer.parseInt(in.readLine());
        System.out.println(scelta);
        switch(scelta){
        case 1:
            //insert calendar
            Calendar ClaudioCal = new Calendar();
            ClaudioCal.setSummary("Esempio di calendario di Claudio");
            ClaudioCal.setTimeZone("America/Los_Angeles");

            cale = service.calendars().insert(ClaudioCal).execute();
            break;

            //other case.......

        System.out.println("Fatto");
    }
    }

Credential credential = OAuth2Native.authorize(
    HTTP_TRANSPORT, JSON_FACTORY, new LocalServerReceiver(),
    Arrays.asList(CalendarScopes.CALENDAR));

// set up global Calendar instance
client = com.google.api.services.calendar.Calendar.builder(HTTP_TRANSPORT, JSON_FACTORY)
    .setApplicationName("Google-CalendarSample/1.0").setHttpRequestInitializer(credential)
    .build();

com.google.api.services.calendar.Calendar service =
    new com.google.api.services.calendar.Calendar(httpTransport,
                                                  jsonFactory);

com.google.api.services.calendar.Calendar service =
    new com.google.api.services.calendar.Calendar(httpTransport,
                                                  accessProtectedResource,
                                                  jsonFactory);