JAVA ON GOOGLE CLOUD PLATFORM

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Build, Deploy, Debug, and Monitor Highly Scalable Java Applications

• Build Java apps on GCP using Eclipse, IntelliJ, or browser based command-line
• Deploy and scale Spring Boot or Spark Java apps
• Use Maven or Gradle build tool plugins to build and deploy to GCP
• Query fully-managed MySQL, PostgreSQL, or NoSQL databases on GCP using Java
• Deploy Java apps to a managed Kubernetes cluster
• Run apps on Google maintained OpenJDK or OpenJDK+Jetty9 Docker images

A Broad Set Of Idiomatic Java APIs & Libraries

Store & archive data within Cloud Storage

Set up fully-managed event-driven messaging with Pub/Sub

Query public data using BigQuery

Translate text in different languages with the Translation API

Analyze images using the Vision API

Store & archive data within Cloud Storage

1

Set up a Cloud Platform Console project

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Set up a GCP Console project.

   Set up a project

   Click to:

   • Create or select a project.
   • Enable the Cloud Storage API for that project.
   • Create a service account.
   • Download a private key as JSON.

   You can view and manage these resources at any time in the GCP Console.

3. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

   Example: Linux or macOS

   Replace [PATH] with the file path of the JSON file that contains your service account key.

   export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

   Example: Windows

   Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

   With PowerShell:

   $env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   $env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

   With command prompt:

   set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

2

Set up a Cloud Storage Bucket

Create a Cloud Storage Bucket:

gsutil mb gs://[YOUR-BUCKET-NAME]

Make the bucket publicly readable so it can serve file:

gsutil defacl set public-read gs://[YOUR_BUCKET_NAME]

3

Add maven dependencies to pom.xml

View on GitHub

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-storage</artifactId>
  <version>1.22.0</version>
</dependency>

4

Add environment variables to app.yaml

View on GitHub

env_variables:
  BUCKET_NAME: YOUR-BUCKET-NAME

5

Write your code

View on GitHub

@SuppressWarnings("serial")
@WebServlet(name = "upload", value = "/upload")
@MultipartConfig()
public class UploadServlet extends HttpServlet {

  private static final String BUCKET_NAME = System.getenv("BUCKET_NAME");
  private static Storage storage = null;

  @Override
  public void init() {
    storage = StorageOptions.getDefaultInstance().getService();
  }

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException,
      ServletException {
    final Part filePart = req.getPart("file");
    final String fileName = filePart.getSubmittedFileName();

    // Modify access list to allow all users with link to read file
    List<Acl> acls = new ArrayList<>();
    acls.add(Acl.of(Acl.User.ofAllUsers(), Acl.Role.READER));
    // the inputstream is closed by default, so we don't need to close it here
    Blob blob =
        storage.create(
            BlobInfo.newBuilder(BUCKET_NAME, fileName).setAcl(acls).build(),
            filePart.getInputStream());

    // return the public download link
    resp.getWriter().print(blob.getMediaLink());
  }
}

Set up fully-managed event-driven messaging with Pub/Sub.

1

Set up a Cloud Platform Console project

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Set up a GCP Console project.

   Set up a project

   Click to:

   • Create or select a project.
   • Enable the Cloud Pub/Sub API for that project.
   • Create a service account.
   • Download a private key as JSON.

   You can view and manage these resources at any time in the GCP Console.

3. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

   Example: Linux or macOS

   Replace [PATH] with the file path of the JSON file that contains your service account key.

   export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

   Example: Windows

   Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

   With PowerShell:

   $env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   $env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

   With command prompt:

   set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

2

Create a topic and subscription

gcloud beta pubsub topics create YOUR_TOPIC_NAME

gcloud beta pubsub subscriptions create YOUR_SUBSCRIPTION_NAME --topic YOUR_TOPIC_NAME

3

Add maven dependencies to pom.xml

View on GitHub

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-pubsub</artifactId>
  <version>0.40.0-beta</version>
</dependency>

4

Write your code to publish and receive messages

Publish Messages

View on GitHub

import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutureCallback;
import com.google.api.core.ApiFutures;
import com.google.api.gax.rpc.ApiException;
import com.google.cloud.ServiceOptions;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.ProjectTopicName;
import com.google.pubsub.v1.PubsubMessage;

public class PublisherExample {

  // use the default project id
  private static final String PROJECT_ID = ServiceOptions.getDefaultProjectId();

  /** Publish messages to a topic.
   * @param args topic name, number of messages
   */
  public static void main(String... args) throws Exception {
    // topic id, eg. "my-topic"
    String topicId = args[0];
    int messageCount = Integer.parseInt(args[1]);
    ProjectTopicName topicName = ProjectTopicName.of(PROJECT_ID, topicId);
    Publisher publisher = null;
    try {
      // Create a publisher instance with default settings bound to the topic
      publisher = Publisher.newBuilder(topicName).build();

      for (int i = 0; i < messageCount; i++) {
        String message = "message-" + i;

        // convert message to bytes
        ByteString data = ByteString.copyFromUtf8(message);
        PubsubMessage pubsubMessage = PubsubMessage.newBuilder()
            .setData(data)
            .build();

        //schedule a message to be published, messages are automatically batched
        ApiFuture<String> future = publisher.publish(pubsubMessage);

        // add an asynchronous callback to handle success / failure
        ApiFutures.addCallback(future, new ApiFutureCallback<String>() {

          @Override
          public void onFailure(Throwable throwable) {
            if (throwable instanceof ApiException) {
              ApiException apiException = ((ApiException) throwable);
              // details on the API exception
              System.out.println(apiException.getStatusCode().getCode());
              System.out.println(apiException.isRetryable());
            }
            System.out.println("Error publishing message : " + message);
          }

          @Override
          public void onSuccess(String messageId) {
            // Once published, returns server-assigned message ids (unique within the topic)
            System.out.println(messageId);
          }
        });
      }
    } finally {
      if (publisher != null) {
        // When finished with the publisher, shutdown to free up resources.
        publisher.shutdown();
      }
    }
  }
}

Subscribe to Messages

View on GitHub

import com.google.cloud.ServiceOptions;
import com.google.cloud.pubsub.v1.AckReplyConsumer;
import com.google.cloud.pubsub.v1.MessageReceiver;
import com.google.cloud.pubsub.v1.Subscriber;
import com.google.pubsub.v1.ProjectSubscriptionName;
import com.google.pubsub.v1.PubsubMessage;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;

public class SubscriberExample {

  // use the default project id
  private static final String PROJECT_ID = ServiceOptions.getDefaultProjectId();

  private static final BlockingQueue<PubsubMessage> messages = new LinkedBlockingDeque<>();

  static class MessageReceiverExample implements MessageReceiver {

    @Override
    public void receiveMessage(PubsubMessage message, AckReplyConsumer consumer) {
      messages.offer(message);
      consumer.ack();
    }
  }

  /** Receive messages over a subscription. */
  public static void main(String... args) throws Exception {
    // set subscriber id, eg. my-sub
    String subscriptionId = args[0];
    ProjectSubscriptionName subscriptionName = ProjectSubscriptionName.of(
        PROJECT_ID, subscriptionId);
    Subscriber subscriber = null;
    try {
      // create a subscriber bound to the asynchronous message receiver
      subscriber =
          Subscriber.newBuilder(subscriptionName, new MessageReceiverExample()).build();
      subscriber.startAsync().awaitRunning();
      // Continue to listen to messages
      while (true) {
        PubsubMessage message = messages.take();
        System.out.println("Message Id: " + message.getMessageId());
        System.out.println("Data: " + message.getData().toStringUtf8());
      }
    } finally {
      if (subscriber != null) {
        subscriber.stopAsync();
      }
    }
  }
}

Perform data analytics with BigQuery

1

Set up a Cloud Platform Console project

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Set up a GCP Console project.

   Set up a project

   Click to:

   • Create or select a project.
   • Enable the BigQuery API for that project.
   • Create a service account.
   • Download a private key as JSON.

   You can view and manage these resources at any time in the GCP Console.

3. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

   Example: Linux or macOS

   Replace [PATH] with the file path of the JSON file that contains your service account key.

   export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

   Example: Windows

   Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

   With PowerShell:

   $env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   $env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

   With command prompt:

   set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

2

Add maven dependencies to pom.xml

View on GitHub

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-bigquery</artifactId>
  <version>1.22.0</version>
</dependency>

3

Write Your Code

Create a BigQuery service object

View on GitHub

BigQuery bigquery = BigQueryOptions.getDefaultInstance().getService();

Query Public Data

View on GitHub

QueryJobConfiguration queryConfig =
    QueryJobConfiguration.newBuilder(
      "SELECT "
          + "CONCAT('https://stackoverflow.com/questions/', CAST(id as STRING)) as url, "
          + "view_count "
          + "FROM `bigquery-public-data.stackoverflow.posts_questions` "
          + "WHERE tags like '%google-bigquery%' "
          + "ORDER BY favorite_count DESC LIMIT 10")
        // Use standard SQL syntax for queries.
        // See: https://cloud.google.com/bigquery/sql-reference/
        .setUseLegacySql(false)
        .build();

// Create a job ID so that we can safely retry.
JobId jobId = JobId.of(UUID.randomUUID().toString());
Job queryJob = bigquery.create(JobInfo.newBuilder(queryConfig).setJobId(jobId).build());

// Wait for the query to complete.
queryJob = queryJob.waitFor();

// Check for errors
if (queryJob == null) {
  throw new RuntimeException("Job no longer exists");
} else if (queryJob.getStatus().getError() != null) {
  // You can also look at queryJob.getStatus().getExecutionErrors() for all
  // errors, not just the latest one.
  throw new RuntimeException(queryJob.getStatus().getError().toString());
}

Displaying Results

View on GitHub

// Get the results.
QueryResponse response = bigquery.getQueryResults(jobId);

TableResult result = queryJob.getQueryResults();

// Print all pages of the results.
for (FieldValueList row : result.iterateAll()) {
  String url = row.get("url").getStringValue();
  long viewCount = row.get("view_count").getLongValue();
  System.out.printf("url: %s views: %d%n", url, viewCount);
}

Translate text in different languages with the Translation API

1

Set up a Cloud Platform Console project

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Set up a GCP Console project.

   Set up a project

   Click to:

   • Create or select a project.
   • Enable the Cloud Translation API for that project.
   • Create a service account.
   • Download a private key as JSON.

   You can view and manage these resources at any time in the GCP Console.

3. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

   Example: Linux or macOS

   Replace [PATH] with the file path of the JSON file that contains your service account key.

   export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

   Example: Windows

   Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

   With PowerShell:

   $env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   $env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

   With command prompt:

   set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

2

Add maven dependencies to pom.xml

View on GitHub

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-translate</artifactId>
  <version>1.22.0</version>
</dependency>

3

Write Your Code

View on GitHub

// Imports the Google Cloud client library
import com.google.cloud.translate.Translate;
import com.google.cloud.translate.Translate.TranslateOption;
import com.google.cloud.translate.TranslateOptions;
import com.google.cloud.translate.Translation;

public class QuickstartSample {
  public static void main(String... args) throws Exception {
    // Instantiates a client
    Translate translate = TranslateOptions.getDefaultInstance().getService();

    // The text to translate
    String text = "Hello, world!";

    // Translates some text into Russian
    Translation translation =
        translate.translate(
            text,
            TranslateOption.sourceLanguage("en"),
            TranslateOption.targetLanguage("ru"));


    System.out.printf("Text: %s%n", text);
    System.out.printf("Translation: %s%n", translation.getTranslatedText());
  }
}

Analyze images using the Vision API

1

Set up a Cloud Platform Console project

1. Sign in to your Google Account.

   If you don't already have one, sign up for a new account.

2. Set up a GCP Console project.

   Set up a project

   Click to:

   • Create or select a project.
   • Enable the Cloud Vision API for that project.
   • Create a service account.
   • Download a private key as JSON.

   You can view and manage these resources at any time in the GCP Console.

3. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

   Example: Linux or macOS

   Replace [PATH] with the file path of the JSON file that contains your service account key.

   export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

   Example: Windows

   Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

   With PowerShell:

   $env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

   For example:

   $env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

   With command prompt:

   set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

2

Add maven dependencies to pom.xml

View on GitHub

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-vision</artifactId>
  <version>1.22.0</version>
</dependency>

3

Write Your Code

Get Vision Service

View on GitHub

/**
 * Connects to the Vision API using Application Default Credentials.
 */
public static Vision getVisionService() throws IOException, GeneralSecurityException {
  GoogleCredential credential =
      GoogleCredential.getApplicationDefault().createScoped(VisionScopes.all());
  JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
  return new Vision.Builder(GoogleNetHttpTransport.newTrustedTransport(), jsonFactory, credential)
          .setApplicationName(APPLICATION_NAME)
          .build();
}

Detect Face

View on GitHub

/**
 * Gets up to {@code maxResults} faces for an image stored at {@code path}.
 */
public List<FaceAnnotation> detectFaces(Path path, int maxResults) throws IOException {
  byte[] data = Files.readAllBytes(path);

  AnnotateImageRequest request =
      new AnnotateImageRequest()
          .setImage(new Image().encodeContent(data))
          .setFeatures(ImmutableList.of(
              new Feature()
                  .setType("FACE_DETECTION")
                  .setMaxResults(maxResults)));
  Vision.Images.Annotate annotate =
      vision.images()
          .annotate(new BatchAnnotateImagesRequest().setRequests(ImmutableList.of(request)));
  // Due to a bug: requests to Vision API containing large images fail when GZipped.
  annotate.setDisableGZipContent(true);

  BatchAnnotateImagesResponse batchResponse = annotate.execute();
  assert batchResponse.getResponses().size() == 1;
  AnnotateImageResponse response = batchResponse.getResponses().get(0);
  if (response.getFaceAnnotations() == null) {
    throw new IOException(
        response.getError() != null
            ? response.getError().getMessage()
            : "Unknown error getting image annotations");
  }
  return response.getFaceAnnotations();
}

Highlight faces

View on GitHub

/**
 * Reads image {@code inputPath} and writes {@code outputPath} with {@code faces} outlined.
 */
private static void writeWithFaces(Path inputPath, Path outputPath, List<FaceAnnotation> faces)
    throws IOException {
  BufferedImage img = ImageIO.read(inputPath.toFile());
  annotateWithFaces(img, faces);
  ImageIO.write(img, "jpg", outputPath.toFile());
}

/**
 * Annotates an image {@code img} with a polygon around each face in {@code faces}.
 */
public static void annotateWithFaces(BufferedImage img, List<FaceAnnotation> faces) {
  for (FaceAnnotation face : faces) {
    annotateWithFace(img, face);
  }
}

/**
 * Annotates an image {@code img} with a polygon defined by {@code face}.
 */
private static void annotateWithFace(BufferedImage img, FaceAnnotation face) {
  Graphics2D gfx = img.createGraphics();
  Polygon poly = new Polygon();
  for (Vertex vertex : face.getFdBoundingPoly().getVertices()) {
    poly.addPoint(vertex.getX(), vertex.getY());
  }
  gfx.setStroke(new BasicStroke(5));
  gfx.setColor(new Color(0x00ff00));
  gfx.draw(poly);
}

JAVA QUICK STARTS

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Deploy, manage, and scale web applications and APIs with ease in Google’s PaaS.

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Kubernetes Engine

Use Kubernetes to build powerful container-based applications.

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Compute Engine

Use cloud-based virtual machines to build and deploy your application.

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Google APIs

Learn how to unlock Google’s services using these Java APIs.

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Find and Fix Production Issues

Google Stackdriver provides tracing, debugging logging, monitoring, and reporting capabilities. It equips you with insights into the health, performance, and availability of cloud-powered applications, enabling you to find and fix issues production faster.

Tracing

Collect latency data on your apps. Inspect trace data collected with reports.

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Debugging

Debug live production workloads without stopping or breaking code execution.

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Logging

Use Java client libraries to send output log statements to Stackdriver.

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Reporting

Analyze errors across multiple services and get alerts in real-time.

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Monitoring

Gather metrics across disk, CPU, network, or even third-party applications.

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Tutorials

Java guides and walkthroughs

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Articles

Java blog posts and coverage

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APIs & Libraries

Java client libraries

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Tools

Eclipse and IntelliJ plugins, Google Cloud SDK, among others

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SpringBoot on GCP

Deploy a SpringBoot app on Google App Engine

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Spring Cloud GCP

Bring Spring programming model to Google Cloud Platform APIs

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JAVA ON GCP COMMUNITIES

Got something to say? Join our community to ask questions, or just chat with the experts at Google who help build the support for Java on Google Cloud Platform.

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