@juliobarros For local “Api Gateway” there’s this for SAM https://github.com/awslabs/aws-sam-local and this for Serverless https://github.com/dherault/serverless-offline I have experience only from the latter and it was bad ~3-4 months ago. Dunno if it has gotten any better. My current workflow is to unit-test the handler functions locally and test the GW stuff directly on AWS.
I attended AWS Serverless Architectural Best Practices webinar yesterday and the presenter advertised his graphical tool for designing simple Serverless AWS architectures https://sbd.danilop.net/. You can connect blocks like lambda functions and dynamo-db tables and it can output infra code as Serverless YML / SAM / Terraform. It’s not complete but something to help you get started… But it doesn’t support Java as target runtime..