The backend is developed with Java, version 1.7, and uses Maven for dependency management. MongoDB is used as a datastore.
The backend is set up using Maven. Maven uses its own standardized project and folder structure.
You can use any editor or tool you like as long as it support the Maven project structure. If the tool does not support Maven then you can also use the command line Maven tool.
A good starting point (besides the really well structured website of dropwizard itself) is the XDropWizard project on GitHub. It shows how to get the different parts together in a dropwizard project.