Google - Service Account Usage (Example: read from a Blogger site)

BloggerReadPostList.java

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
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.blogger.Blogger;
import com.google.api.services.blogger.BloggerScopes;
import com.google.api.services.blogger.model.Blog;
import com.google.api.services.blogger.model.Post;
import com.google.api.services.blogger.model.PostList;

import java.io.FileInputStream;
import java.util.Collections;

public class BloggerReadPostList {
    public static void main(String[] args) throws Exception {

        final String BLOG_URL = "http://attivissimo.blogspot.com";
        final String CRED_FILE_PATH = System.getProperty("user.home") + "/credentials.json";
        final String APPLICATION_NAME = "SampleBloggerReading";

        final HttpTransport HTTP_TRANSPORT = new NetHttpTransport();
        final JsonFactory JSON_FACTORY = new JacksonFactory();

        // Specify "Authorization Scope" [BloggerScopes.BLOGGER = "https://www.googleapis.com/auth/blogger"]
        GoogleCredential credential = GoogleCredential
                .fromStream(new FileInputStream(CRED_FILE_PATH))
                .createScoped(Collections.singleton(BloggerScopes.BLOGGER));

        Blogger blogger = new Blogger.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential)
                .setApplicationName(APPLICATION_NAME).build();

        String blogId = blogger.blogs().getByUrl(BLOG_URL).execute().getId();

        // Start from first page
        Blogger.Posts.List action = blogger.posts().list(blogId).setPageToken(null);

        // Restrict the result content to just the data we need.
        action.setFields("items(author/displayName,id,content,published,title,url),nextPageToken");
        action.setMaxResults(10L);

        // This step sends the request to the server.
        PostList list = action.execute();

        for (Post post: list.getItems()) System.out.println("[" + post.getId() + "] " + post.getTitle());
        System.out.println("Next token = " + list.getNextPageToken());
    }
}

credentials.json

{
    "type": "service_account",
    "project_id": "...",
    "private_key_id": "...",
    "private_key": "...",
    "client_email": "...",
    "client_id": "...",
    "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    "token_uri": "https://oauth2.googleapis.com/token",
    "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
    "client_x509_cert_url": "..."
}

pom.xml

    <dependency>
        <groupId>com.google.apis</groupId>
        <artifactId>google-api-services-blogger</artifactId>
        <version>v3-rev61-1.25.0</version>
    </dependency>

    <dependency>
        <groupId>com.google.http-client</groupId>
        <artifactId>google-http-client-jackson2</artifactId>
        <version>1.39.2</version>
    </dependency>