example that register bucket notifications to some pub/sub topic in GCP

GcpCreateNotification.java

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.jackson.JacksonFactory;
import com.google.api.services.storage.Storage;
import com.google.api.services.storage.StorageScopes;
import com.google.api.services.storage.model.Notification;
import com.google.cloud.storage.Bucket;
import com.google.gson.JsonObject;
import java.io.FileInputStream;
import java.util.Collections;
public class GooglePubSubClient {

    public static void main(String[] args) {
        try {
            
            String bucketName = "some-bucket";
            String credentials = "your creds";
            String topicId = "//pubsub.googleapis.com/projects/your-project/topics/your-topic";

            final GoogleCredential googleCredential = GoogleCredential
                    .fromStream(new FileInputStream(pathToFileWithCredentials))
                    .createScoped(Collections.singletonList(StorageScopes.DEVSTORAGE_FULL_CONTROL));
            final Storage storage = new Storage.Builder(new NetHttpTransport(), new JacksonFactory(), googleCredential).build();

            Notification notification = new Notification();
            notification.setTopic(topicId);
            notification.setPayloadFormat("JSON_API_V1");

            Notification v = storage.notifications().insert(bucketName, notification).execute();
            System.out.println(v);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}