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Reading labels works but reading messages results in ACCESS_TOKEN_SCOPE_INSUFFICIENT

I have created one poc using Gmail API which read all email and print on console. I have take refrence from Gmail api Java quickstart.
I have follows all the steps like create project, Gmail API enable, OAuth credentials in google cloud console
The problem is, when I run the code all the labels are printed successfully but I'm not able to read mail messages. Some an error are getting which are below:
> Task :GmailQuickstart.main()
Labels:
- CHAT
- SENT
- INBOX
- IMPORTANT
- TRASH
- DRAFT
- SPAM
- CATEGORY_FORUMS
- CATEGORY_UPDATES
- CATEGORY_PERSONAL
- CATEGORY_PROMOTIONS
- CATEGORY_SOCIAL
- STARRED
- UNREAD
Exception in thread "main" com.google.api.client.googleapis.json.GoogleJsonResponseException: 403 Forbidden
GET https://gmail.googleapis.com/gmail/v1/users/me/messages
{
"code": 403,
"details": [
{
"#type": "type.googleapis.com/google.rpc.ErrorInfo",
"reason": "ACCESS_TOKEN_SCOPE_INSUFFICIENT"
}
],
"errors": [
{
"domain": "global",
"message": "Insufficient Permission",
"reason": "insufficientPermissions"
}
],
"message": "Request had insufficient authentication scopes.",
"status": "PERMISSION_DENIED"
}
at com.google.api.client.googleapis.json.GoogleJsonResponseException.from(GoogleJsonResponseException.java:146)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:118)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:37)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest$1.interceptResponse(AbstractGoogleClientRequest.java:439)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1111)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:525)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:466)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:576)
at GmailQuickstart.main(GmailQuickstart.java:80)
> Task :GmailQuickstart.main() FAILED
Execution failed for task ':GmailQuickstart.main()'.
> Process 'command '/home/bhautik/Downloads/jdk-11.0.15.1_linux-x64_bin/data/usr/lib/jvm/jdk-11/bin/java'' finished with non-zero exit value 1
* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
And my code was below:
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.Label;
import com.google.api.services.gmail.model.ListLabelsResponse;
import com.google.api.services.gmail.model.ListMessagesResponse;
import com.google.api.services.gmail.model.Message;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/* class to demonstrate use of Gmail list labels API */
public class GmailQuickstart {
private static final String APPLICATION_NAME = "Gmail API Java Quickstart";
private static final JsonFactory JSON_FACTORY = GsonFactory.getDefaultInstance();
private static final String TOKENS_DIRECTORY_PATH = "tokens";
private static final List<String> SCOPES = Collections.singletonList(GmailScopes.GMAIL_LABELS);
private static final String CREDENTIALS_FILE_PATH = "/credentials.json";
private static final String USER_ID = "me";
private static Credential getCredentials(final NetHttpTransport HTTP_TRANSPORT)
throws IOException {
// Load client secrets.
InputStream in = GmailQuickstart.class.getResourceAsStream(CREDENTIALS_FILE_PATH);
if (in == null) {
throw new FileNotFoundException("Resource not found: " + CREDENTIALS_FILE_PATH);
}
GoogleClientSecrets clientSecrets =
GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));
// Build flow and trigger user authorization request.
GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
HTTP_TRANSPORT, JSON_FACTORY, clientSecrets, SCOPES)
.setDataStoreFactory(new FileDataStoreFactory(new java.io.File(TOKENS_DIRECTORY_PATH)))
.setAccessType("offline")
.build();
LocalServerReceiver receiver = new LocalServerReceiver.Builder().setPort(8888).build();
Credential credential = new AuthorizationCodeInstalledApp(flow, receiver).authorize("user");
//returns an authorized Credential object.
return credential;
}
public static void main(String... args) throws IOException, GeneralSecurityException {
// Build a new authorized API client service.
final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
Gmail service = new Gmail.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials(HTTP_TRANSPORT))
.setApplicationName(APPLICATION_NAME)
.build();
// Print the labels in the user's account.
String user = "me";
ListLabelsResponse listResponse = service.users().labels().list(user).execute();
List<Label> labels = listResponse.getLabels();
if (labels.isEmpty()) {
System.out.println("No labels found.");
} else {
System.out.println("Labels:");
for (Label label : labels) {
System.out.printf("- %s\n", label.getName());
}
}
// Print the message
ListMessagesResponse response = service.users().messages().list(USER_ID).execute();
// List<Message> messages = response.getMessages();
List<Message> messages = new ArrayList<Message>();
while (response.getMessages() != null) {
messages.addAll(response.getMessages());
if (response.getNextPageToken() != null) {
String pageToken = response.getNextPageToken();
response = service.users().messages().list(USER_ID).setPageToken(pageToken).execute();
} else {
break;
}
}
for (Message message : messages) {
System.out.println(message.getId());
System.out.println(message.getPayload());
Message test = service.users().messages().get("me", message.getId()).execute();
System.out.println(test.getSnippet());
}
}
}

ACCESS_TOKEN_SCOPE_INSUFFICIENT is a very common error message. It comes from copying the example without understanding what its doing. This is googles fault for not explaining things better.
The quick start uses the lables.list method. This method runs on users private data so you used Oauth2 to request permission of the user to access their data.
The method can run with any of the following permissions being requested
Best practice is to only request the permissions you need. So the code is asking for the GmailScopes.GMAIL_LABELS permission which will only give you access to see the lables
Now to read a users messages the messges.listmethod you need to request permission with one of the following scopes
as you can see the label scope is not there. Thats because you need a higher level of permissions to access this data..
Solution:
Change the scope in your code to request one of the scopes needed for messgaes.list.
Then you need to reauthorize your application. YOu can do this in a few was.
delete the file found in TOKENS_DIRECTORY_PATH
change .authorize("user"); the text passed here to something else.
When you run your app again it should prompt you for authorization again.

I would comment but I have too few rep.
I guess you didn't properly set up the permissions of your access token. The error message suggessts, that you need a specific set of permissions to access the ressource

How to build a Compute client using the Google API Services SDK in Java

I'm trying to build a Compute client based on a key .JSON file. I'm looking at the examples found here but they are outdated and not working anymore.
I can't find any example in the current offical docs here.
Here is what I'm currently trying:
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.compute.Compute;
import com.google.api.services.compute.model.Instance;
import com.google.api.services.compute.model.InstanceList;
import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
public class Application {
private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
public static void main(String[] args) throws IOException, GeneralSecurityException {
InputStream credentialsJSON = Application.class.getClassLoader().getResourceAsStream("mykey.json");
JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
GoogleCredential cred = GoogleCredential.fromStream(credentialsJSON ,httpTransport,JSON_FACTORY);
// Create Compute Engine object for listing instances.
Compute compute = new Compute.Builder(httpTransport, JSON_FACTORY, cred.getRequestInitializer())
.setApplicationName("myapplication")
.build();
InstanceList instanceList = compute.instances().list("PROJECT_NAME", "europe-west3-a").execute();
for (Instance instance : instanceList.getItems()) {
System.out.println(instance.getId());
}
}
}
But it throws the following error:
Exception in thread "main" com.google.api.client.googleapis.json.GoogleJsonResponseException: 401 Unauthorized
{
"code" : 401,
"errors" : [ {
"domain" : "global",
"location" : "Authorization",
"locationType" : "header",
"message" : "Login Required.",
"reason" : "required"
} ],
"message" : "Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.",
"status" : "UNAUTHENTICATED"
}
I don't understand because the file get's parsed correctly. Also the GoogleCredential model I'm using seems to be deprecated.

You need these two dependencies:
<dependencies>
<dependency>
<groupId>com.google.apis</groupId>
<artifactId>google-api-services-compute</artifactId>
<version>v1-rev20200311-1.30.9</version>
</dependency>
<dependency>
<groupId>com.google.auth</groupId>
<artifactId>google-auth-library-oauth2-http</artifactId>
<version>0.20.0</version>
</dependency>
</dependencies>
The google-auth-library-oauth2-http dependency repository can be found here. Switching to this new method worked for me.
And here's the working code:
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.compute.Compute;
import com.google.api.services.compute.ComputeScopes;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
public class GCPComputeClientHelper {
private static Compute compute = null;
protected GCPComputeClientHelper() {
// Exists only to defeat instantiation
}
public static Compute getComputeInstance() throws GeneralSecurityException, IOException {
if (compute == null) {
compute = build();
}
return compute;
}
private static Compute build() throws GeneralSecurityException, IOException {
// Create http transporter needed for Compute client
HttpTransport HTTP_TRANSPORTER = GoogleNetHttpTransport.newTrustedTransport();
// Read GCP service account credentials JSON key file
InputStream serviceAccountJsonKey = GCPComputeClientHelper.class.getClassLoader().getResourceAsStream("mykeyfile.json");
// Authenticate based on the JSON key file
GoogleCredentials credentials = GoogleCredentials.fromStream(serviceAccountJsonKey);
credentials = credentials.createScoped(ComputeScopes.CLOUD_PLATFORM);
HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(credentials);
// Create and return GCP Compute client
return new Compute.Builder(HTTP_TRANSPORTER, JacksonFactory.getDefaultInstance(), requestInitializer)
.setApplicationName("myapplication")
.build();
}
}

Read/Write Google sheet via Server without using OAuth

Tried going through the internet and google docs they provide OAuth way only. Is there a way to read/write to google sheets with API Key and not OAuth.

After some research, Credential object from google-oath-client module can help. Download the .p12 file from the google account. Code for reading a google sheet without OAUth prompt below. This can also be used to write or append sheets with some modification :
package com.mycomp;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
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.gson.GsonFactory;
import com.google.api.services.sheets.v4.Sheets;
import com.google.api.services.sheets.v4.SheetsScopes;
import com.google.api.services.sheets.v4.model.ValueRange;
import com.nm.vernacular.services.SpreadSheetsService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;
import java.security.GeneralSecurityException;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
/**
* Created by ankushgupta & modified for SO.
*/
public class GoogleSheetsReader {
private static final JsonFactory JSON_FACTORY = GsonFactory.getDefaultInstance();
private static final String KEY_FILE_LOCATION = "<Name of p12 file>.p12";
private static final String SERVICE_ACCOUNT_EMAIL = "<email of google service account>";
private static final String APPLICATION_NAME = "Google Sheets API";
private static final Logger LOGGER = LoggerFactory.getLogger(GoogleSheetsReader.class);
/**
* Global instance of the scopes required by this quickstart.
* If modifying these scopes, delete your previously saved credentials/ folder.
*/
private static final List<String> SCOPES = Collections.singletonList(SheetsScopes.SPREADSHEETS);
/**
* Creates an authorized Credential object.
* #return An authorized Credential object.
* #throws IOException If there is no client_secret.
*/
private Credential getCredentials() throws URISyntaxException, IOException, GeneralSecurityException {
//Reading Key File
URL fileURL = GoogleSheetsReader.class.getClassLoader().getResource(KEY_FILE_LOCATION);
// Initializes an authorized analytics service object.
if(fileURL==null) {
fileURL = (new File("/resources/"+ KEY_FILE_LOCATION)).toURI().toURL();
}
// Construct a GoogleCredential object with the service account email
// and p12 file downloaded from the developer console.
HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
return new GoogleCredential.Builder()
.setTransport(httpTransport)
.setJsonFactory(JSON_FACTORY)
.setServiceAccountId(SERVICE_ACCOUNT_EMAIL)
.setServiceAccountPrivateKeyFromP12File(new File(fileURL.toURI()))
.setServiceAccountScopes(SCOPES)
.build();
}
#Override
public List<Object[]> readSheet(String nameAndRange, String key, int[] returnRange) throws GeneralSecurityException, IOException {
final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
final String spreadsheetId = key;
final String range = nameAndRange;
try {
Sheets service = new Sheets.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials())
.setApplicationName(APPLICATION_NAME)
.build();
ValueRange response = service.spreadsheets().values()
.get(spreadsheetId, range)
.execute();
List<List<Object>> values = response.getValues();
int a = returnRange.length;
List<Object[]> result = new LinkedList<>();
if (values == null || values.isEmpty()) {
return Collections.emptyList();
} else {
for (List row : values) {
if(row.size() >= a) {
Object[] objArr = new Object[a];
for(int i=0;i<a;i++) {
objArr[i] = row.get(returnRange[i]);
}
result.add(objArr);
}
}
}
return result;
} catch(Exception ex) {
LOGGER.error("Exception while reading google sheet", ex);
} finally {
}
return null;
}
public static void main(String[] args) {
GoogleSheetsReader reader = new GoogleSheetsReader();
reader.readSheet("<Sheet Name>!A2:B", "<sheets key from URL>", new int[]{0, 1});
}
}

Based from this documentation, when your application requests public data, the request doesn't need to be authorized, but does need to be accompanied by an identifier, such as an API key.
Every request your application sends to the Google Sheets API needs to identify your application to Google. There are two ways to identify your application: using an OAuth 2.0 token (which also authorizes the request) and/or using the application's API key. Here's how to determine which of those options to use:
If the request requires authorization (such as a request for an individual's private data), then the application must provide an OAuth 2.0 token with the request. The application may also provide the API key, but it doesn't have to.
If the request doesn't require authorization (such as a request for public data), then the application must provide either the API key or an OAuth 2.0 token, or both—whatever option is most convenient for you.
However, there are some scopes which require OAuth authorization. Check this link: Access Google spreadsheet API without Oauth token.

Using API key, you can read from google sheets, but only if the sheet is shared with public.
However to write to google sheets, you must you OAuth. See this link.

Need help on Google API Calendar V3 Java and OAUTH2

i'm trying to handle my Google Agenda by using the Google Calendar APi V3( Java ).
However, i'm quite new to this and to OAUTH2 .. then i've searched for examples and i found one here :
Google Calendar API V3 Java: Unable to use 'primary' for Calendars:get
Here is the code :
import java.io.IOException;
import java.util.Collections;
import java.util.Scanner;
import java.util.Set;
import com.google.api.client.auth.oauth2.AuthorizationCodeFlow;
import com.google.api.client.auth.oauth2.AuthorizationCodeRequestUrl;
import com.google.api.client.auth.oauth2.AuthorizationCodeTokenRequest;
import com.google.api.client.auth.oauth2.TokenResponse;
import com.google.api.client.extensions.auth.helpers.Credential;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.http.HttpRequestInitializer;
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.jackson2.JacksonFactory;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.Calendar.CalendarList;
import com.google.api.services.calendar.CalendarScopes;
import com.google.api.services.calendar.model.CalendarListEntry;
public class App {
public static void main(String[] args) throws IOException{
//Two globals that will be used in each step.
HttpTransport httpTransport = new NetHttpTransport();
JsonFactory jsonFactory = new JacksonFactory();
//Create the authorization code flow manager
Set<String> scope = Collections.singleton(CalendarScopes.CALENDAR);
String clientId = "xxxxxx.apps.googleusercontent.com";
String clientSecret = "xxxxxxxxxxx";
//Use a factory pattern to create the code flow
AuthorizationCodeFlow.Builder codeFlowBuilder =
new GoogleAuthorizationCodeFlow.Builder(
httpTransport,
jsonFactory,
clientId,
clientSecret,
scope
);
AuthorizationCodeFlow codeFlow = codeFlowBuilder.build();
//set the code flow to use a dummy user
//in a servlet, this could be the session id
String userId = "ipeech";
//"redirect" to the authentication url
String redirectUri = "https://www.example.com/oauth2callback";
AuthorizationCodeRequestUrl authorizationUrl = codeFlow.newAuthorizationUrl();
authorizationUrl.setRedirectUri(redirectUri);
System.out.println("Go to the following address:");
System.out.println(authorizationUrl);
//use the code that is returned as a url parameter
//to request an authorization token
System.out.println("What is the 'code' url parameter?");
String code = new Scanner(System.in).nextLine();
AuthorizationCodeTokenRequest tokenRequest = codeFlow.newTokenRequest(code);
tokenRequest.setRedirectUri(redirectUri);
TokenResponse tokenResponse = tokenRequest.execute();
//Now, with the token and user id, we have credentials
com.google.api.client.auth.oauth2.Credential credential = codeFlow.createAndStoreCredential(tokenResponse, userId);
//Credentials may be used to initialize http requests
HttpRequestInitializer initializer = credential;
//and thus are used to initialize the calendar service
Calendar.Builder serviceBuilder = new Calendar.Builder(
httpTransport, jsonFactory, initializer);
serviceBuilder.setApplicationName("Example");
Calendar calendar = serviceBuilder.build();
//get some data
String calendarID = "xxxxxxxxxxx";
getCalendarListSummary(calendarID,calendar);
getAllCalendarListSummary(calendar);
//getCalendarSummary(calendarID,calendar);
}
public static void getCalendarListSummary(String calendarID, Calendar calendar) throws IOException{
CalendarListEntry calendarListEntry = calendar.calendarList().get(calendarID).execute();
System.out.println(calendarListEntry.getSummary());
}
public static void getAllCalendarListSummary (Calendar calendar) throws IOException{
Calendar.CalendarList.List listRequest = calendar.calendarList().list();
com.google.api.services.calendar.model.CalendarList feed = listRequest.execute();
for(CalendarListEntry entry:feed.getItems()){
System.out.println("ID: " + entry.getId());
System.out.println("Summary: " + entry.getSummary());
}
}
When i launch the programm, it asks me to give the authorization code ("What is the 'code' url parameter?") but i don't know where to find it .. Any ideas ?

In this example, there is a part that says "Go to the following address:" you have to copy that url, paste it in the browser and then you will receive the authorization code. Copy that code and paste it after "What is the 'code' url parameter?" and press "Enter" so the program can continue.
This is a basic example and that why the OAuth 2 flow is done that way.
Here is a complete example of a Google calendar java program. I would suggest to first understand how OAuth 2 works, how to create projects in the Developer console and how to create credentials for those projects. Then it would be easier to understand and use the complete example.

GmailApiQuickstart -

I am embarrassed that I'm simply failing with an example piece of code, but I'll blame it on the fact that it is late...
I have taken a copy and paste of: https://developers.google.com/gmail/api/quickstart/quickstart-java
and downloaded the client libraries: https://code.google.com/p/google-api-java-client/
and https://developers.google.com/api-client-library/java/apis/gmail/v1
When I run the sample, I get the following exception:
Exception in thread "main" java.lang.IllegalArgumentException
at com.google.api.client.repackaged.com.google.common.base.Preconditions.checkArgument(Preconditions.java:76)
at com.google.api.client.util.Preconditions.checkArgument(Preconditions.java:37)
at com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets.getDetails(GoogleClientSecrets.java:82)
at com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow$Builder.<init>(GoogleAuthorizationCodeFlow.java:195)
at com.emailreply.musterion.GmailApiQuickstart.main(GmailApiQuickstart.java:40)
Googling, I can't find a simple answer, so am assuming stupidity or a library missing/incorrect.
The libraries as I have them are:
/libs/commons-logging-1.1.1.jar
/libs/google-api-client-1.19.0.jar
/libs/google-api-client-android-1.19.0.jar
/libs/google-api-client-appengine-1.19.0.jar
/libs/google-api-client-gson-1.19.0.jar
/libs/google-api-client-jackson2-1.19.0.jar
/libs/google-api-client-java6-1.19.0.jar
/libs/google-api-client-servlet-1.19.0.jar
/libs/google-http-client-1.19.0.jar
/libs/google-http-client-android-1.19.0.jar
/libs/google-http-client-appengine-1.19.0.jar
/libs/google-http-client-gson-1.19.0.jar
/libs/google-http-client-jackson2-1.19.0.jar
/libs/google-http-client-jdo-1.19.0.jar
/libs/google-oauth-client-1.19.0.jar
/libs/google-oauth-client-appengine-1.19.0.jar
/libs/google-oauth-client-java6-1.19.0.jar
/libs/google-oauth-client-jetty-1.19.0.jar
/libs/google-oauth-client-servlet-1.19.0.jar
/libs/gson-2.1.jar
/libs/httpclient-4.0.1.jar
/libs/httpcore-4.0.1.jar
/libs/jackson-core-2.1.3.jar
/libs/jdo2-api-2.3-eb.jar
/libs/jetty-6.1.26.jar
/libs/jetty-util-6.1.26.jar
/libs/jsr305-1.3.9.jar
/libs/transaction-api-1.1.jar
google-api-services-gmail-v1-rev10-1.19.0.jar
The example mentioned above:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.auth.oauth2.GoogleOAuthConstants;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
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.jackson2.JacksonFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.model.ListThreadsResponse;
import com.google.api.services.gmail.model.Thread;
public class GmailApiQuickstart {
// Check https://developers.google.ciom/gmail/api/auth/scopes for all available scopes
private static final String SCOPE = "https://www.googleapis.com/auth/gmail.readonly";
private static final String APP_NAME = "Gmail API Quickstart";
// Email address of the user, or "me" can be used to represent the currently authorized user.
private static final String USER = "me";
// Path to the client_secret.json file downloaded from the Developer Console
private static final String CLIENT_SECRET_PATH = "./client_secret.json";
public static void main (String [] args) throws IOException {
HttpTransport httpTransport = new NetHttpTransport();
JsonFactory jsonFactory = new JacksonFactory();
GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(jsonFactory, new BufferedReader(new InputStreamReader(GmailApiQuickstart.class.getResourceAsStream(CLIENT_SECRET_PATH))));
// Allow user to authorize via url.
GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
httpTransport, jsonFactory, clientSecrets, Arrays.asList(SCOPE))
.setAccessType("online")
.setApprovalPrompt("auto").build();
String url = flow.newAuthorizationUrl().setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI).build();
System.out.println("Please open the following URL in your browser then type the authorization code:\n" + url);
// Read code entered by user.
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String code = br.readLine();
// Generate Credential using retrieved code.
GoogleTokenResponse response = flow.newTokenRequest(code)
.setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI).execute();
GoogleCredential credential = new GoogleCredential()
.setFromTokenResponse(response);
// Create a new authorized Gmail API client
Gmail service = new Gmail.Builder(httpTransport, jsonFactory, credential)
.setApplicationName(APP_NAME).build();
// Retrieve a page of Threads; max of 100 by default.
ListThreadsResponse threadsResponse = service.users().threads().list(USER).execute();
List<Thread> threads = threadsResponse.getThreads();
// Print ID of each Thread.
for (Thread thread : threads) {
System.out.println("Thread ID: " + thread.getId());
}
}
}
I replaced the reference to CLIENT_SECRET_PATH with:
new BufferedReader(new InputStreamReader(GmailApiQuickstart.class.getResourceAsStream(CLIENT_SECRET_PATH)))
for no other reason than to try something different. It does work and reads the file correctly.
Any ideas?

Right, after some more research (asking a colleague/genius), I found the problem. Basically the GoogleClientSecrets object was not being properly bound with the information from my client_secrets.json file. This meant that during authentication, objects were null resulting in the IllegalArgumentException.
So the original file which looked like this:
{
"private_key_id": "zzz",
"private_key": "-----BEGIN PRIVATE KEY-----\nxyz\n-----END PRIVATE KEY-----\n",
"client_email": "1234#developer.gserviceaccount.com",
"client_id": "1wdfghyjmp.apps.googleusercontent.com",
"type": "service_account"
}
was edited to look like this:
{
"web" : {
"private_key_id": "zzz",
"private_key": "-----BEGIN PRIVATE KEY-----\nxyz\n-----END PRIVATE KEY-----\n",
"client_email": "1234#developer.gserviceaccount.com",
"client_id": "1wdfghyjmp.apps.googleusercontent.com",
"type": "service_account"
}
}
This allowed me to progress through the code with authentication.
Hope this helps.

here is a working example of non-interactive auth for Google Non-interactive authorization with Google OAuth2
the problem is not in "web" tag in the client json, but rather in the fact that their example is for web authentication while their suggested way of generating credentials is for non-interactive "service account". they have multiple problems with their documentation.