Building a Scalable CRUD Apps with AWS Lambda and DynamoDB in Java

In today’s cloud computing landscape, serverless architectures have gained immense popularity due to their scalability, cost-efficiency, and ease of management. AWS Lambda, coupled with DynamoDB, offers a powerful combination for developing serverless applications.

In this comprehensive guide, we will delve into the process of building robust and scalable serverless applications using AWS Lambda and DynamoDB in Java. From setting up the DynamoDB table to writing Lambda functions and deploying the application, we will cover each step in detail. Let’s embark on a journey to harness the power of serverless computing with AWS Lambda and DynamoDB.


Before we begin, it is assumed that you have a basic understanding of AWS Lambda, DynamoDB, and Java programming. Make sure you have the AWS SDK for Java installed and configured in your local development environment. Additionally, an active AWS account is required to follow the hands-on exercises.

🔸Step 1: Setting up the DynamoDB Table:

To store data for our serverless application, we need to set up a DynamoDB table. Let’s follow these steps:
Access the AWS Management Console and navigate to the appropriate section for DynamoDB table setup.

Create a new table with a suitable name and define the primary key, such as “id.” You can add additional attributes based on your application’s requirements.

Related read: Everything You Need to Know about Web Application Architecture

🔸Step 2: Before writing the Lambda function, let’s configure the AWS Lambda environment:

1. To get started, create a new Java project in your preferred Integrated Development Environment (IDE).
2. Add the necessary dependencies, such as the AWS SDK for Java, to your project.
3. Create a new Java class that will act as the entry point for your Lambda function. Import the required AWS SDK libraries.

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🔸Step 3: Now, let’s dive into writing the Lambda function:

1. This function will handle the CRUD operations for our serverless application:

public class CrudLambdaHandler implements RequestHandler<Request, Response> {
public Response handleRequest(Request request, Context context) {
// Implementation goes here

2. Establish a connection with the DynamoDB table: Inside the handleRequest method, create an instance of the AmazonDynamoDBClient class from the AWS SDK. Use it to connect to the DynamoDB table you created in Step 1.

AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard().build();
DynamoDB dynamoDB = new DynamoDB(client);
Table table = dynamoDB.getTable("your_table_name");

3. Implement the CRUD operations: Within the handleRequest method, write the code for the CRUD operations based on your application’s requirements. Here are some examples:

Create Operation:

Item item = new Item().withPrimaryKey("id", request.getId())
.withString("title", request.getTitle())
.withString("description", request.getDescription())
.withBoolean("status", request.getStatus());

Read Operation:

Item item = table.getItem("id", request.getId());
Response response = new Response(item.getString("title"), item.getString("description"), item.getBoolean("status"));

Update Operation:

UpdateItemSpec updateItemSpec = new UpdateItemSpec()
.withPrimaryKey("id", request.getId())
.withUpdateExpression("set #titleAttr = :titleValue, #descAttr = :descValue, #statusAttr = :statusValue")
.withNameMap(new NameMap().with("#titleAttr", "title").with("#descAttr", "description").with("#statusAttr", "status"))
.withValueMap(new ValueMap().withString(":titleValue", request.getTitle())
.withString(":descValue", request.getDescription())
.withBoolean(":statusValue", request.getStatus()));

Delete Operation:

table.deleteItem("id", request.getId());

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🔸Step 4: Implementation and Validation of the Lambda Function:

Now to deploy and test your Lambda function follow these steps:

1. Package your Lambda function code, along with its compiled class files and dependencies, into a single JAR (Java Archive) file.
2. Access the AWS Management Console, navigate to AWS Lambda, and create a new function.
3. Configure the function’s runtime, handler, and necessary permissions.
4. Upload the JAR file containing your Lambda function code.
5. Once the function is deployed, use the Test tab in the AWS Lambda console to invoke it with sample data and verify its functionality.



In this blog post, we embarked on a journey to develop a scalable serverless CRUD application using AWS Lambda and DynamoDB in Java. We covered the essential steps, including setting up the DynamoDB table, configuring the AWS Lambda function, writing the CRUD operations, and deploying and testing the function. By following this guide, you have gained the knowledge and skills to create your own serverless applications on the AWS platform. Enjoy building your scalable and cost-effective applications with AWS Lambda and DynamoDB!

For more information, you can check out my GitHub.

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