AWS Lambda is the core service in AWS for building serverless applications. You can run code without provisioning servers. You pay only for the time you run your code, unlike EC2 where you pay for the time the server is up. Lambda also takes care of high availability. You can invoke Lambdas from other AWS services, console, or AWS CLI.

In this recipe, we will create a Lambda in Java and deploy it using the AWS management console. In the next recipe, we will also explore AWS CLI to deploy Lambda. In later recipes and chapters, we will see how we can automate most of the deployment tasks using Amazon CloudWatch templates similar to how most enterprise projects do.