As well as deploying code via Heroku Button, you can of course deploy from an existing codebase that has working code. For each of the supported languages we have a sample app that you can deploy, to quickly understand the basic workflow when using Heroku.
In this section we will develop a Java application and deployment deploy it to Heroku. Along the way you will have a better appreciation of how Heroku works.
Apart from language specific differences, i.e. build tools & processes, Heroku works the same for all other languages and frameworks. So you can use one of the other sample apps if you prefer, or even use your own projects.
Later on in the workshop we will give you several Play Framework applications to work with, which also integrate with the Salesforce Force.com platform.