Components are an important way to think about applications. Components allow you freedom to evolve the application by packaging it in different ways and allowing you to create new functionality. Component architecture is very much in line with the Java philosophy of developing small pieces that can be downloaded on demand. As the Java industry evolves, a traditional application will probably become much more like a framework into which components from multiple vendors are put. Components would be dynamically added by users in services of a particular task.
Users construct the final application.
It's like putting together a house. You'll see vendors, like Gamelan, selling components. Manufacturing and retail will use the net for mass customization. Today you can actually get customized jeans made for your particular body type. In the near future I believe you might see the use of Java agents or objects that represent you on the Web, so that all the information about your body, its size, contour, and so on is in one place, and can be used by the manufacturer to guide the production of clothes, shoes, or any number of different items and deliver them to you direct.