You need an active AWS account, and read and follow the Getting started section of the recipes, Your first AWS Lambda and Your first Lambda with AWS CLI to set up Java, Maven, the parent project, serverless-cookbook-parent-aws-java,  and AWS CLI, and other code usage guidelines.

This recipe also assumes you are familiar with general software development concepts and practices such as dependency injection, unit testing, and coding to interfaces. Familiarity with libraries such as JUnit and Mockito will be good to have.