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Deploying a web application using the Java Servlet API

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Updated at June 3, 2025

Learn how to use serverless technology and Java Servlet API to create a simple web application for managing a task list.

To create a web app:

  1. Get your cloud ready.
  2. Set up your environment.
  3. Create a Yandex Object Storage bucket.
  4. Create a YDB.
  5. Create Yandex Cloud Functions.
  6. Create an API gateway.
  7. Test your application.

If you no longer need the resources you created, delete them.

Getting started

Sign up in Yandex Cloud and create a billing account:

  1. Navigate to the management console and log in to Yandex Cloud or register a new account.
  2. On the Yandex Cloud Billing page, make sure you have a billing account linked and it has the ACTIVE or TRIAL_ACTIVE status. If you do not have a billing account, create one and link a cloud to it.

If you have an active billing account, you can navigate to the cloud page to create or select a folder for your infrastructure to operate in.

Learn more about clouds and folders.

The cost of resources to support a web application includes:

Set up your environment

  1. Create a service account and assign it the editor role for your folder.

  2. Clone the repository with the project:

    git clone https://github.com/yandex-cloud-examples/yc-serverless-servlet

  3. Add the contents of the yc-serverless-servlet local repository you cloned to the servlet.zip archive. You will need this archive later to create Yandex Cloud Functions.

Create an Object Storage bucket

Create a bucket and upload index.html into it:

  1. In the management console, select the folder where you want to create a bucket.
  2. Select Object Storage.
  3. Click Create bucket.
  4. On the bucket creation page:
    1. Enter a name for the bucket as per the naming requirements.
    2. Limit the maximum bucket size, if required.
    3. In the Object read access, Object listing access, and Read access to settings fields, select Restricted.
    4. Select the default storage class.
    5. Click Create bucket to complete the operation.
  5. Select the bucket you created.
  6. Click Upload and select src/main/resources/index.html in the project directory.
  7. Select the storage class for the file and click Upload.

Create a database in Managed Service for YDB

  1. Create a database in serverless mode:

    1. In the management console, select the folder where you created the bucket.

    2. Select Managed Service for YDB.

    3. Click Create a database.

    4. Specify a Name for the database. Follow these naming requirements:

      • It must be from 2 to 63 characters long.
      • It can only contain lowercase Latin letters, numbers, and hyphens.
      • It must start with a letter and cannot end with a hyphen.

    5. Under Database type, select Serverless.

    6. Click Create a database.

    7. Wait until the database is up and running. While being created, your database will have the Provisioning status. Once it is ready for use, its status will change to Running.

    8. Select the created database.

    9. Under Connection, find the Endpoint field and save its value. You will need it when creating functions.

  2. Create a table named Tasks:

    1. In the management console, select the folder where you created the database.

    2. Select Managed Service for YDB.

    3. Select the database on the Databases page.

    4. To open the DB root directory, navigate to the Navigation tab.

    5. To make a database query, click New SQL query in the top-right corner. The Query page will open.

    6. In the Query field, enter:

      CREATE TABLE Tasks (
  TaskId Utf8,
  Name Utf8,
  Description Utf8,
  CreatedAt Datetime,
  PRIMARY KEY (TaskId)
);

    7. Click Run.

    Run this request:

    ydb -e grpcs://<YDB_endpoint> -d <DB_name> \
scripting yql -s \
"CREATE TABLE Tasks
(
  TaskId Utf8,
  Name Utf8,
  Description Utf8,
  CreatedAt Datetime,
  PRIMARY KEY (TaskId)
);"

Create Cloud Functions

Create a function for each servlet:

  1. In the management console, navigate to the folder where you created the bucket and the database.
  2. Select Cloud Functions.
  3. Click Create function.
  4. Enter a name, e.g., add-task, and description for the function.
  5. Click Create.
  6. Under Editor, select java21 as the runtime environment, disable Add files with code examples, and click Continue.
  7. Set up the function code. To do this, select ZIP archive in the Method field.
  8. In the File field, click Attach file and select servlet.zip you created earlier.
  9. In the Entry point field, enter yandex.cloud.examples.serverless.todo.AddTaskServlet.
  10. Set Timeout to 10.
  11. In the Service account field, specify the account you created when setting up your environment.
  12. Add these environment variables:
    • ENDPOINT: Enter the first part of the Endpoint field value you saved when creating your YDB (the one between grpcs:// and /?database=), e.g., ydb.serverless.yandexcloud.net:2135.
    • DATABASE: Enter the second part of the Endpoint field value you saved when creating your YDB (the one following /?database=), e.g., /ru-central1/r1gra875baom********/g5n22e7ejfr1********.
  13. Click Save changes.
  14. On the Overview page, enable Public function.
  15. Repeat steps 3 through 14 to create a function named list-tasks with the yandex.cloud.examples.serverless.todo.ListTasksServlet entry point.
  16. Repeat steps 3 through 14 to create a function named delete-task with the yandex.cloud.examples.serverless.todo.DeleteTaskServlet entry point.

  1. Create a function named add-task:

    yc serverless function create --name=add-task

    Result:

    id: d4ejb1799eko********
folder_id: aoek49ghmknn********
created_at: "2021-03-08T14:07:32.134Z"
name: add-task
log_group_id: eolm8aoq9vcp********
http_invoke_url: https://functions.yandexcloud.net/d4ejb1799eko********
status: ACTIVE

  2. Create a version of the add-task function:

    yc serverless function version create \
  --function-name=add-task \
  --runtime java21 \
  --entrypoint yandex.cloud.examples.serverless.todo.AddTaskServlet \
  --memory 128m \
  --execution-timeout 10s \
  --source-path ./servlet.zip \
  --environment DATABASE=<DB_name>,ENDPOINT=<YDB_endpoint>

    Where:

    • --function-name: Name of the function whose version you want to create.
    • --runtime: Runtime environment.
    • entrypoint: Entry point in <function_file_name>.<handler_name> format.
    • --memory: Amount of RAM.
    • --execution-timeout: Maximum function running time before timeout.
    • --source-path: Path to the previously created servlet.zip archive with the function code and required dependencies.
    • --environment: Environment variables in key=value format.

    Result:

    done (1s)
id: d4evvn8obisa********
function_id: d4ejb1799eko********
...
tags:
- $latest
log_group_id: ckg3qh8h363p********

  3. Make the function public:

    yc serverless function allow-unauthenticated-invoke add-task

    Result:

    done (1s)

  4. Repeat steps 1 through 3 to create a function named list-tasks with the yandex.cloud.examples.serverless.todo.ListTasksServlet entry point.

  5. Repeat steps 1 through 3 to create a function named delete-task with the yandex.cloud.examples.serverless.todo.DeleteTaskServlet entry point.

Use the create, createVersion, and setAccessBindings API methods for the Function resource.

You can create a function and its version using Yandex Cloud Toolkit for the JetBrains IntelliJ IDE family.

Create an API gateway

To enable communication between the services, create an API gateway:

  1. In the management console, select the folder where you created your bucket, database, and functions.

  2. Select API Gateway.

  3. Click Create API gateway.

  4. Enter a name and description for the gateway.

  5. In the Specification field, add this specification:

    openapi: 3.0.0
info:
  title: ToDo list
  version: 1.0.0
paths:
  /:
    get:
      x-yc-apigateway-integration:
        type: object-storage
        bucket: <bucket>
        object: index.html
        presigned_redirect: false
        service_account: <service_account>
      operationId: static
  /add:
     post:
       x-yc-apigateway-integration:
         type: cloud-functions
         function_id: <add-task_ID>
       operationId: addTask
  /list:
    get:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <list-tasks_ID>
      operationId: listTasks
  /delete:
    delete:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <delete-task_ID>
      operationId: deleteTask

    Where:

    • bucket: Name of the bucket containing index.html.
    • service_account: ID of the service account you created when setting up your environment.
    • /add section, function_id parameter: add-task function ID.
    • /list section, function_id parameter: list-tasks function ID.
    • /delete section, function_id parameter: delete-task function ID.

  6. Click Create.

  1. Save the following specification to todo.yaml:

    openapi: 3.0.0
info:
  title: ToDo list
  version: 1.0.0
paths:
  /:
    get:
      x-yc-apigateway-integration:
        type: object-storage
        bucket: <bucket>
        object: index.html
        presigned_redirect: false
        service_account: <service_account>
      operationId: static
  /add:
    post:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <add-task_ID>
      operationId: addTask
  /list:
    get:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <list-tasks_ID>
      operationId: listTasks
  /delete:
    delete:
      x-yc-apigateway-integration:
        type: cloud-functions
        function_id: <delete-task_ID>
      operationId: deleteTask

    Where:

    • bucket: Name of the bucket containing index.html.
    • service_account: ID of the service account you created when setting up your environment.
    • /add section, function_id parameter: add-task function ID.
    • /list section, function_id parameter: list-tasks function ID.
    • /delete section, function_id parameter: delete-task function ID.

  2. Create an API gateway:

    yc serverless api-gateway create \
  --name todo-list \
  --spec=todo.yaml \
  --description "simple todo list"

    Result:

    done (41s)
id: d5delqeel34q********
folder_id: b1g86q4m5vej********
created_at: "2021-03-08T14:07:32.134Z"
name: todo-list
description: simple todo list
status: ACTIVE
domain: d5dm1lba80md********.i9******.apigw.yandexcloud.net
log_group_id: ckg2hdmevnvc********

You can create an API gateway using Yandex Cloud Toolkit for the JetBrains IntelliJ IDE family.

Test the application

To open the app, follow the link in the Default domain field of the API gateway you created.

How to delete the resources you created

To stop paying for the resources you created:

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