Java Quickstart

Cloud Functions is a serverless execution environment for building and connecting cloud services. With Cloud Functions you write simple, single-purpose functions that are attached to events emitted from your cloud infrastructure and services. Your function is triggered when an event being watched is fired.

This page shows you how to create and deploy a Java Cloud Function using the Cloud Console. When this function is triggered by an HTTP request, it writes a message:

package com.example;


public class Example implements HttpFunction {
  public void service(HttpRequest request, HttpResponse response) throws Exception {
    BufferedWriter writer = response.getWriter();
    writer.write("Hello world!");

Before you begin

  1. Sign in to your Google Account.

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

  2. In the Cloud Console, on the project selector page, select or create a Cloud project.

    Go to the project selector page

  3. Make sure that billing is enabled for your Google Cloud project. Learn how to confirm billing is enabled for your project.

  4. Enable the Cloud Functions and Cloud Build APIs.

    Enable the APIs

Create a function

  1. Open the Functions Overview page in the Cloud Console:

    Go to the Cloud Functions Overview page

    Make sure that the project for which you enabled Cloud Functions is selected.

  2. Click Create function.

  3. Name your function.

  4. In the Trigger field, select HTTP.

  5. In the Authentication field, select Allow unauthenticated invocations.

  6. Click Save to save your changes, and then click Next.

  7. In the Source code field, select Inline editor. In this exercise, you will use the default function provided in the editor.

  8. Use the Runtime dropdown to select the desired Java runtime.

Deploy the function

  1. At the bottom of the page, click Deploy.

  2. After clicking Deploy, Cloud Console redirects to the Cloud Functions Overview page.

    While the function is being deployed, the icon next to it is a small spinner. After it finishes deploying, the spinner turns to a green check mark:

    Screenshot that shows function deployment process

Test the function

  1. Display the menu for your function, and click Test function.

    Screenshot that shows function testing process

  2. On the testing page, click Test the function.

    The Output screen displays the text "Hello World!"

  3. Now change the message. In the Triggering Event field, enter the text {"message":"Hello, YOUR_NAME!"}, replacing YOUR_NAME with a name, and click Test the function.

    For example, suppose you entered the name "Rowan". In the Output field, you would see the message Hello, Rowan!.

    In the Logs field, a status code of 200 indicates success.

    Screenshot showing Logs field with 200 code, indicating success

View logs

Check the logs to see your actions in the log history:

  • Back on the Cloud Functions Overview page, display the menu for your function, and click View logs.

Your log history appears.

Screenshot showing Logs field with 200 code, indicating success

What's next