Java Enterprise/Web development

A web application is a website, but it has more functionality than a typical website has. It usually represents a complex domain model that is persisted to a database, has a custom user interface and it often integrates with different (soap or rest) webservices. A web application might involve implementing complex decision making or software driven business process management.

In these cases, a custom built web application is for you.
Typically, this won't be the typical kind of site on the internet, but a site that is running on the local network within a company, offering functionality very specific to the business.