I have created "My First Elastic Beanstalk Application" on amazon aws. I also choose tomcat as a web/app server. It shows that every thing is up and running. So how I check out the code base and you know, make some changes and deploy it back to the app server.
Basically except seeing there dashboard. I don't really know what this sample application does, is it a web page does it return a json, and where the code base etc...
You can create a tomcat based application on your local desktop. You can then prepare a war file or a zip file containing your web app. You can then deploy it to your environment by uploading this zip file using Elastic Beanstalk console.
You can go through the Getting Started walkthrough: http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/GettingStarted.Walkthrough.html
This shows you how to move forward from the Sample application you have already launched. You can also find the source code of the sample application here: https://elasticbeanstalk-us-east-1.s3.amazonaws.com/resources/elasticbeanstalk-sampleapp2.war
This is one way of doing it. You can also deploy code to Elastic Beanstalk using an Eclipse plugin: Guides on deploying applications using Eclipse: http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/create_deploy_Java.html http://d1un85p0f2qstc.cloudfront.net/eclipse/elasticbeanstalk/index.html